andrologia 11 (4): 243-249
Received March 15, 1979
(1979)
Fertility Unit, Department of Obstetrics and Gynaecology, University of Utrecht, The Netherlands
The Significance of Antoni van Leeuwenhoek for the Early Development of Andrology J . KREMER
Andrology can be defined as the science of physiology and pathology of the male genital organs, so far these concern the reproductive functions. The founder of this science is not a scientist in the classic sense of the word, but an unlettered amateur-microscopist, Antoni van Leeuwenhoek, born in the Durch city of Delft in 1673 (Fig. 1). He was trained as a drapery salesman and started a trade in cloth and haberdashery in Delft in 1654. It is likely that van Leeuwenhoek used a magnifying glass to study the textile tissues and, in this way developed his hobby i.e. microscopic investigations. The microscopes, which van Leeuwenhoek used for his investigations were all single microscopes. Although compound microscopes with two lenses already existed, van Leeuwenhoek preferred the single microscope because it produced a very clear image. Van Leeuwenhoek ground the lenses himself and during his life constructed more than 500 microscopes, of which only nine are still in existence. The best specimen of van Leeuwenhoek’s microscope, kept at Utrecht in the Netherlands, has been shown to have a diameter magnification of 270 and a resolving power of 1.4 micron (Fig. 2). In 1660 van Leeuwenhoek was appointed as an usher of the townhall of Delft and later on, after an education for surveyor, also as a winegauger. In 1663 he was accepted as a correspondent of “The Royal Society for improving of Natural Knowledge”, referred to as “The Royal Society”. He had been introduced to this prestigious international scientific organization by this famous medical townsman, Reinier de Graaf, the discoverer of the ovulation process and the corpus luteum formation. To be a correspondent of “The Royal Society” was of great importance, because accepted letters were published in the “Philosophical Transaction” and sent to the important scientific centers of Europe. “The Royal Society’’ and the “Philosophical Transactions” are still in existence today. In 1680 “The Royal Society” offered him a fellowship because of his important microscopic discoveries. In 1716, the Louvain College of Professors “The Wild Boar” paid great homage to van Leeuwenhoek by striking a silver medal (Fig. 3) with the portrait of van Leeuwenhoek on one side and a bee-hive on the other yith the legend “In tenui labor at tenuis non gloria” (your work is with the small, your fame is not small). In 1723 van Leeuwenhoek died, almost 91 years old. It is a peculiar thing, but characteristic for the time after van Leeuwenhoek, that his spermatological findings were kept in secrecy. Between 1798 and 1807 the “Select works of A. van Leeuwenhoek” were published. All the passages which were considered to be offensive to many readers were omitted; so this edition of the letters does not mention van Leeuwenhoek’s work concerning the spermatozoa. It lasted until the late fifties of the 20th century before van Leeuwenhoek’s spermatological investigations received the appreciation which they deserved. Key words: Leeuwenhoek - andrology, development of - ovulism - animalculism - spermatozoa -
Ham
244
J. Kremer
Fig. 1: Antoni van Leeuwenhoek Fig. 2: One of van Leeuwenhoeks’ microscopes A) Lens, B) Objectholder, C) Screw to move the objectholder, D) Screw to move the lensholder, E) Pen to f i i the microscope to a wooden table.
Van Leeuwenhoek never wrote a book, only letters. From these letters, most of them sent to the “Royal College” in London, he comes across to us as a patient and persevering investigator, gifted with extra-ordinarily keen vision and powers of observation. Modest and accessible to the opinion of others, but conscious of his own worth and thouroughly honest. His honesty is evident in his letter concerning the discovery of the spermatozoa. In this letter, sent in November 1677, he attributed this important discovery to the student Johan Ham, a native of the Dutch city of Arnhem, who studied philosophy and medicine in Leiden, a University city in the neighbourhood of Delft. Ham finished his studies in 1680, practised as a physician in Arnhem for only a short period and continued his career in politics. In his letter of November 1677 van Leeuwenhoek wrote: “When MI. Ham visited me, he brought with him, in a small phial, the spontaneously discharged semen of a man who had visited a woman of dubious nature, saying that he had seen living animalcules in it, judging these animalcules to have tails and not to remain alive more than twenty-four hours.” “This gentleman also reported that he had noticed that the animalcules were dead after the patient had taken turpentine” (considered to be a remedy for gonorrhoea). “In the presence of Mr. Ham I examined some of this matter which I introduced in a glass tube and saw some living creatures in, but when 1 examined the same matter by myself after the lapse of two to three hours, I observed that they were dead.” andrologia 11 (1979)
Early Development of Andrology
245
Fig. 3: Silver medal,struck in honour of van Leeuwenhoek bij the Louvain College of Professors “The Wild Boar”.
It is unlikely that the man, whose semen was investigated by Ham and van Leeuwenhoek, really suffered from gonorrhoea. The spontaneously discharged fluid from a gonorrhoe patient contains many leucocytes but no motile spermatozoa. It is therefore more likely that the material, which MI. Ham took to van Leeuwenhoek, was masturbation semen from a man who was afraid that he had got a veneral disease and therefore asked Mr. Ham for an examination of his “discharge”. It is evident that Ham must have had a very good microscope as he could see the tails of the spermatozoa. Hence it was not just the so-called possession of “a good glass” which gave van Leeuwenhoek the lead, it was his inborn genius. Ham’s discovery excited van Leeuwenhoek’s curiosity and stimulated him towards further independent research. He found the animalcules also in the ejaculate of a healthy man and he proved in this way that Ham’s opinion, the animalcules should be a manifestation of a venereal disease, was wrong. Van Leeuwenhoek was uncertain about the acceptance of his letter in which he described the findings, because despite of the relatively liberal attitude towards sexuality during the so-called “Golden Age” of the Netherlands, masturbation was considered an immoral act at the time. Therefore van Leeuwenhoek wrote: “What I investigate is only what, without sinfulfy defiling myself, remains as a residue after conjugal coitus.” So it is likely that van Leeuwenhoek used the latter part of his own ejaculate for his examinations. Another indication for this supposition is the following sentence from the same letter: “I have often examined the same material from a healthy man, . . . not liquefied after the lapse of some time, but immediately after ejaculation, before six beats of the pulse had intervened.” Such a procedure is only possible with an own ejaculate and even then it is hard to perform the examination so quickly. Despite of the fact that the investigations took place without masturbation, van Leeuwenhoek thought it useful to finish his letter as follows: “. . . and if your Lordship should consider that these observations may disgust or scandalize the learned, I andrologia 11 (1 979)
246
J. Kremer
Fig. 4: Spermatozoa, drawn by van Leeuwenhoek.
earnestly beg your Lordship to regard them as private and to publish or destroy them, as your Lordship’s judgement dictates.” The delicate nature of the subject was probably the reason for van Leeuwenhoek having had the letter translated into Latin, the scientific language of the day, a tongue he himself was unschooled in. All his other letters, which he sent to “The Royal Society”, also the 57 other letters about his spermatological investigations, were written in the Dutch language, a language which was understood by many London inhabitants during that time. In his letter of November 1677 van Leeuwenhoek described the spermatozoa very precisely and added a drawing on which even the head vacuoles of the spermatozoa were marked (Fig. 4). He wrote: “I have seen so great a number of living animals in it that sometimes more than a thousand were moving about in an amount of material of the size of a grain of sand. These animalcules were smaller than the corpuscles which impart a red colour to the blood so that I judge a million of them would not equal in size a large grain of sand. Their bodies which were round, were blunt in front and ran to a point behind. They were furnished with a thin tail, about five or six times as long as the body and were transparent and with the thickness of about one twentyfifth of the body. They moved forward owing to the motion of their tails like that of a snake or an eel, swimming in water, but in the somewhat thicker substance they would have to lash their tails eight to ten times before they could advance a hair’s breadth. In a letter, sent to the “Royal Society” in 1678 van Leeuwenhoek paid more attention to the thready structures, which he saw in a fresh ejaculate, than to the animalandrologia 11 (1979)
Early Dcvelopmenr of Andrology
247
Fig. 5: “Vessels” in semen, inkdrawing by van Leeuwenhoek (from Phil. Trans XII, 1678).
Fig. 6: Pictures of homunculi in semen, drawn by van Leeuwenhoek and sent to ‘The Royal Society” in order to make ridiculous the publicationsof Dalenpatius
cules. He wrote: “As regards the parts themselves of which the denser substance of the semen is mainly made up, as I have many times observed with wonder, they consist of all manner of great and small vessels, so various and so numerous that I have not the least doubt that they are nerves, arteries and veins (Fig. 5 ) . Indeed I have observed these vessels in such great numbers that I felt convinced that in no full-grown human body are there any vessels which cannot be found likewise in sound semen . . . I conceived that the vessels might perhaps serve for the conveyance of the animal spirit.” With this conception van Leeuwenhoek gave to understand that he was a believer of the “School of Ovulism”. According to this philosophy, advocated by the Italian investigator Malpighi and the Dutch investigators de Graaf and Swammerdam, the human body was present in miniature in the ovum. In the opinion of the ovulists, the male semen was nothing but a vehicle of a certain “volatile animal spirit”, impressing on the ovum the perception of life. The “Ovulism” was a philosophy which threatened the important position of the man as the producer of the human body. andrologia 11 (1979)
248
J. Kremer
The latter conception was based on the ideas of Empedocles (5th century BC) and Aristoteles (4th century BC). Empedocles thought that the loose parts of the body were present in the semen and were united to a human body in the uterus. Aristoteles believed that not the actual but the potential components of the human body were available in the semen. The discovery of the animalcules in the semen opened new perspectives for the followers of Empedocles and Aristoteles. In his letter of April 25, 1679, van Leeuwenhoek wrote that in each of the animalcules a preformed miniature human being, a homunculus, might be present. The only task of the woman in the process of reproduction should be to offer her uterus as a “seed-bed”, where one of the homunculi could grow. In his letter of November 12, 1680, van Leeuwenhoek recanted his former statement about the thready structures in a fresh ejaculate. He wrote: “I now totally reject this, because I had the experience that the weaving picture was brought about by accident.” The discovery of spermatozoa in the uterus of a bitch after coitus in 1685 by van Leeuwenhoek was for the animalculists a strong argument against the ovulists. The ovulists had always pointed to the fact that seminal fluid had never been found in the uterus or in the tubes after coitus; therefore only the volatile “animal spirit” could reach the ovum. Although van Leeuwenhoek believed in the presence of a homunculus in the spermatozoon, he did not let his imagination influence his capacity for accurate and detached scientific observation. In a letter of 1699 he wrote: “I put this down as a certain truth that the shape of a human body is included in the animalcules of the male seed . . . but that we should be able to see or to discover the entire shape of a human body, I cannot comprehend.” Van Leeuwenhoek wrote this letter especially to combat De la Plantade, who wrote under the name Dalenpatius. Dalenpatius declared that he had seen human spermatozoa with the shape of a little human body: head, trunk, arms and legs could clearly be distinguished. In order to show how ridiculous Dalenpatius’ idea was, van Leeuwenhoek included in his own letter two drawings, based on Dalenpatius’ publication (Fig. 6). This has led to the misunderstanding, even in the modern literature, that van Leeuwenhoek himself has described such forms. The conflict between ovulists and animalculists was not only a scientific but also a social and even a theological affair. The ovulists stated that a female homunculus in an ovum contained ova, again with homunculi and so on. Therefore Mother Eva’s ovaries had contained ova in which all the coming human beings were present ,,generation packed in generation”. So the ovulists had a biological base for the doctrine of Preformation. A well known Dutch physician, who belonged to the ,,School of Animalculists”, was Herman Boerhaave. It was not till 1875, when Hertwig observed the nuclear fusion of sperm and ovum, that it became clear that the genetic contribution to a new human being comes from man and woman in an equal amount. Antoni van Leeuwenhoek’s spermatological studies lasted more than 40 years. Apart from human spermatozoa, he also described the spermatozoa of mammals, birds, amphibians, fishes, arthropods and moluscs. He demonstrated that the testis is the site of spermproduction and the epididymis the place, where the spermatozoa achieve their motility. He showed that the duration of motility of dog spermatozoa at room temperature in the seminal plasma, was 4-7 days. Contrary to the ideas of prominent scientists of the time, he adhered to hls opinion that the animalcules were a normal component of the semen and necessary for procreation. This conception familiar to us, was not acandrologia 11 (1979)
Early Development of Andrology
249
ceptable for many contemporaries of van Leeuwenhoek. It should last for about two centuries before van Leeuwenhoek’s conception was accepted in the whole scientific world. Even in 1844 the famous German physiologist Miiller stated, that the animalcules in semen were parasites! May it be that van Leeuwenhoek must share the place as discoverer of the spermatozoa with Johan Ham, the basical work in the foundation of Andrology was done by
him. Bibliography AUe de brieven van Antoni van Leeuwenhoek, uitgegeven, geillustreerd en van aantekeningen voorzien door een commissie van NEDERLANDSE Geleerden. Publisher: Swets en Zeitlinger, Amsterdam 1939-1967.
Address: Prof. Dr. J. Kremer, Parklaan 16, Groningen/The Netherlands.
I
I
Gross, R. und P. Schoimerich (Hrsg.): Lehrbuch der inneren Medizin, 5., vollig neubearbeitete Auflage. Stuttgart: Schattauer 1977. LII, 1255 S . , mit 513 z.T. farb. Abb., 31 1 Tab. und 81 farb. Abb. auf 12 Tafeln. DM loo,-. Die 5. Auflage dieses bekannten Buches ist vollig neu uberarbeitet. Allein die Zahl der Abbildungen wurde u m ca. 20%, die Zahl der Tabellen u m ca. 50% erhoht. Dennoch gelang es den insgesamt 5 1 Fachleuten, ohne wesentliche Texterweiterung (etwa 10%) alle wichtigen neuen Daten in ihrem Sachgebiet iibersichtlich und umfassend darzustellen. Davon interessiert den Andrologen nicht nur das Kapitel von Bettendorf und Schirren, in dem ausfiihrlich auf die Erkrankungen der mannlichen und weiblichen Gonaden und speziell auf hormonelle Dysregulationen wahrend der Entwicklungs-, Reifungs- und Alterungsperiode des Organismus eingegangen wird. Denn auch in anderen Abschnitten dieses Buches werden andrologische Fragen beriihrt bzw. beantwortet; so z.B. die Fragen iiber Intersexualitat, insbesondere chromosomal bedingte MiDbildungen in dem Kapitel von Overzier sowie iiber Tumoren der mannlichen Genitalorgane in dem Kapitel von Hohenfellner und Altwin. Diese Kapitel enthalten in der gewunschten knappen Form alles wesentliche, was nicht nur der Student (auch nach der neuen AO) sondern jeder praktisch und klinisch tatige Arzt iiber das Fach Andrologie wissen m u & Auf alle weiteren Einzelheiten verweist die Literaturauswahl a m Ende der jeweiligen Kapitel. Die instruktiven Tabellen, Graphiken und Abbildungen erganzen den Text und sind wesentlich fiir die Empfehlung dieses Buches - speziell auch fur den andrologisch tatigen Arzt. Bei der hervorragenden Ausstattung ist der Preis angemessen. B. Schutte (Hamburg)
andrologia 11 (1979)
I I
BoolcReview
Received March 15, 1979
(1979)
Fertility Unit, Department of Obstetrics and Gynaecology, University of Utrecht, The Netherlands
The Significance of Antoni van Leeuwenhoek for the Early Development of Andrology J . KREMER
Andrology can be defined as the science of physiology and pathology of the male genital organs, so far these concern the reproductive functions. The founder of this science is not a scientist in the classic sense of the word, but an unlettered amateur-microscopist, Antoni van Leeuwenhoek, born in the Durch city of Delft in 1673 (Fig. 1). He was trained as a drapery salesman and started a trade in cloth and haberdashery in Delft in 1654. It is likely that van Leeuwenhoek used a magnifying glass to study the textile tissues and, in this way developed his hobby i.e. microscopic investigations. The microscopes, which van Leeuwenhoek used for his investigations were all single microscopes. Although compound microscopes with two lenses already existed, van Leeuwenhoek preferred the single microscope because it produced a very clear image. Van Leeuwenhoek ground the lenses himself and during his life constructed more than 500 microscopes, of which only nine are still in existence. The best specimen of van Leeuwenhoek’s microscope, kept at Utrecht in the Netherlands, has been shown to have a diameter magnification of 270 and a resolving power of 1.4 micron (Fig. 2). In 1660 van Leeuwenhoek was appointed as an usher of the townhall of Delft and later on, after an education for surveyor, also as a winegauger. In 1663 he was accepted as a correspondent of “The Royal Society for improving of Natural Knowledge”, referred to as “The Royal Society”. He had been introduced to this prestigious international scientific organization by this famous medical townsman, Reinier de Graaf, the discoverer of the ovulation process and the corpus luteum formation. To be a correspondent of “The Royal Society” was of great importance, because accepted letters were published in the “Philosophical Transaction” and sent to the important scientific centers of Europe. “The Royal Society’’ and the “Philosophical Transactions” are still in existence today. In 1680 “The Royal Society” offered him a fellowship because of his important microscopic discoveries. In 1716, the Louvain College of Professors “The Wild Boar” paid great homage to van Leeuwenhoek by striking a silver medal (Fig. 3) with the portrait of van Leeuwenhoek on one side and a bee-hive on the other yith the legend “In tenui labor at tenuis non gloria” (your work is with the small, your fame is not small). In 1723 van Leeuwenhoek died, almost 91 years old. It is a peculiar thing, but characteristic for the time after van Leeuwenhoek, that his spermatological findings were kept in secrecy. Between 1798 and 1807 the “Select works of A. van Leeuwenhoek” were published. All the passages which were considered to be offensive to many readers were omitted; so this edition of the letters does not mention van Leeuwenhoek’s work concerning the spermatozoa. It lasted until the late fifties of the 20th century before van Leeuwenhoek’s spermatological investigations received the appreciation which they deserved. Key words: Leeuwenhoek - andrology, development of - ovulism - animalculism - spermatozoa -
Ham
244
J. Kremer
Fig. 1: Antoni van Leeuwenhoek Fig. 2: One of van Leeuwenhoeks’ microscopes A) Lens, B) Objectholder, C) Screw to move the objectholder, D) Screw to move the lensholder, E) Pen to f i i the microscope to a wooden table.
Van Leeuwenhoek never wrote a book, only letters. From these letters, most of them sent to the “Royal College” in London, he comes across to us as a patient and persevering investigator, gifted with extra-ordinarily keen vision and powers of observation. Modest and accessible to the opinion of others, but conscious of his own worth and thouroughly honest. His honesty is evident in his letter concerning the discovery of the spermatozoa. In this letter, sent in November 1677, he attributed this important discovery to the student Johan Ham, a native of the Dutch city of Arnhem, who studied philosophy and medicine in Leiden, a University city in the neighbourhood of Delft. Ham finished his studies in 1680, practised as a physician in Arnhem for only a short period and continued his career in politics. In his letter of November 1677 van Leeuwenhoek wrote: “When MI. Ham visited me, he brought with him, in a small phial, the spontaneously discharged semen of a man who had visited a woman of dubious nature, saying that he had seen living animalcules in it, judging these animalcules to have tails and not to remain alive more than twenty-four hours.” “This gentleman also reported that he had noticed that the animalcules were dead after the patient had taken turpentine” (considered to be a remedy for gonorrhoea). “In the presence of Mr. Ham I examined some of this matter which I introduced in a glass tube and saw some living creatures in, but when 1 examined the same matter by myself after the lapse of two to three hours, I observed that they were dead.” andrologia 11 (1979)
Early Development of Andrology
245
Fig. 3: Silver medal,struck in honour of van Leeuwenhoek bij the Louvain College of Professors “The Wild Boar”.
It is unlikely that the man, whose semen was investigated by Ham and van Leeuwenhoek, really suffered from gonorrhoea. The spontaneously discharged fluid from a gonorrhoe patient contains many leucocytes but no motile spermatozoa. It is therefore more likely that the material, which MI. Ham took to van Leeuwenhoek, was masturbation semen from a man who was afraid that he had got a veneral disease and therefore asked Mr. Ham for an examination of his “discharge”. It is evident that Ham must have had a very good microscope as he could see the tails of the spermatozoa. Hence it was not just the so-called possession of “a good glass” which gave van Leeuwenhoek the lead, it was his inborn genius. Ham’s discovery excited van Leeuwenhoek’s curiosity and stimulated him towards further independent research. He found the animalcules also in the ejaculate of a healthy man and he proved in this way that Ham’s opinion, the animalcules should be a manifestation of a venereal disease, was wrong. Van Leeuwenhoek was uncertain about the acceptance of his letter in which he described the findings, because despite of the relatively liberal attitude towards sexuality during the so-called “Golden Age” of the Netherlands, masturbation was considered an immoral act at the time. Therefore van Leeuwenhoek wrote: “What I investigate is only what, without sinfulfy defiling myself, remains as a residue after conjugal coitus.” So it is likely that van Leeuwenhoek used the latter part of his own ejaculate for his examinations. Another indication for this supposition is the following sentence from the same letter: “I have often examined the same material from a healthy man, . . . not liquefied after the lapse of some time, but immediately after ejaculation, before six beats of the pulse had intervened.” Such a procedure is only possible with an own ejaculate and even then it is hard to perform the examination so quickly. Despite of the fact that the investigations took place without masturbation, van Leeuwenhoek thought it useful to finish his letter as follows: “. . . and if your Lordship should consider that these observations may disgust or scandalize the learned, I andrologia 11 (1 979)
246
J. Kremer
Fig. 4: Spermatozoa, drawn by van Leeuwenhoek.
earnestly beg your Lordship to regard them as private and to publish or destroy them, as your Lordship’s judgement dictates.” The delicate nature of the subject was probably the reason for van Leeuwenhoek having had the letter translated into Latin, the scientific language of the day, a tongue he himself was unschooled in. All his other letters, which he sent to “The Royal Society”, also the 57 other letters about his spermatological investigations, were written in the Dutch language, a language which was understood by many London inhabitants during that time. In his letter of November 1677 van Leeuwenhoek described the spermatozoa very precisely and added a drawing on which even the head vacuoles of the spermatozoa were marked (Fig. 4). He wrote: “I have seen so great a number of living animals in it that sometimes more than a thousand were moving about in an amount of material of the size of a grain of sand. These animalcules were smaller than the corpuscles which impart a red colour to the blood so that I judge a million of them would not equal in size a large grain of sand. Their bodies which were round, were blunt in front and ran to a point behind. They were furnished with a thin tail, about five or six times as long as the body and were transparent and with the thickness of about one twentyfifth of the body. They moved forward owing to the motion of their tails like that of a snake or an eel, swimming in water, but in the somewhat thicker substance they would have to lash their tails eight to ten times before they could advance a hair’s breadth. In a letter, sent to the “Royal Society” in 1678 van Leeuwenhoek paid more attention to the thready structures, which he saw in a fresh ejaculate, than to the animalandrologia 11 (1979)
Early Dcvelopmenr of Andrology
247
Fig. 5: “Vessels” in semen, inkdrawing by van Leeuwenhoek (from Phil. Trans XII, 1678).
Fig. 6: Pictures of homunculi in semen, drawn by van Leeuwenhoek and sent to ‘The Royal Society” in order to make ridiculous the publicationsof Dalenpatius
cules. He wrote: “As regards the parts themselves of which the denser substance of the semen is mainly made up, as I have many times observed with wonder, they consist of all manner of great and small vessels, so various and so numerous that I have not the least doubt that they are nerves, arteries and veins (Fig. 5 ) . Indeed I have observed these vessels in such great numbers that I felt convinced that in no full-grown human body are there any vessels which cannot be found likewise in sound semen . . . I conceived that the vessels might perhaps serve for the conveyance of the animal spirit.” With this conception van Leeuwenhoek gave to understand that he was a believer of the “School of Ovulism”. According to this philosophy, advocated by the Italian investigator Malpighi and the Dutch investigators de Graaf and Swammerdam, the human body was present in miniature in the ovum. In the opinion of the ovulists, the male semen was nothing but a vehicle of a certain “volatile animal spirit”, impressing on the ovum the perception of life. The “Ovulism” was a philosophy which threatened the important position of the man as the producer of the human body. andrologia 11 (1979)
248
J. Kremer
The latter conception was based on the ideas of Empedocles (5th century BC) and Aristoteles (4th century BC). Empedocles thought that the loose parts of the body were present in the semen and were united to a human body in the uterus. Aristoteles believed that not the actual but the potential components of the human body were available in the semen. The discovery of the animalcules in the semen opened new perspectives for the followers of Empedocles and Aristoteles. In his letter of April 25, 1679, van Leeuwenhoek wrote that in each of the animalcules a preformed miniature human being, a homunculus, might be present. The only task of the woman in the process of reproduction should be to offer her uterus as a “seed-bed”, where one of the homunculi could grow. In his letter of November 12, 1680, van Leeuwenhoek recanted his former statement about the thready structures in a fresh ejaculate. He wrote: “I now totally reject this, because I had the experience that the weaving picture was brought about by accident.” The discovery of spermatozoa in the uterus of a bitch after coitus in 1685 by van Leeuwenhoek was for the animalculists a strong argument against the ovulists. The ovulists had always pointed to the fact that seminal fluid had never been found in the uterus or in the tubes after coitus; therefore only the volatile “animal spirit” could reach the ovum. Although van Leeuwenhoek believed in the presence of a homunculus in the spermatozoon, he did not let his imagination influence his capacity for accurate and detached scientific observation. In a letter of 1699 he wrote: “I put this down as a certain truth that the shape of a human body is included in the animalcules of the male seed . . . but that we should be able to see or to discover the entire shape of a human body, I cannot comprehend.” Van Leeuwenhoek wrote this letter especially to combat De la Plantade, who wrote under the name Dalenpatius. Dalenpatius declared that he had seen human spermatozoa with the shape of a little human body: head, trunk, arms and legs could clearly be distinguished. In order to show how ridiculous Dalenpatius’ idea was, van Leeuwenhoek included in his own letter two drawings, based on Dalenpatius’ publication (Fig. 6). This has led to the misunderstanding, even in the modern literature, that van Leeuwenhoek himself has described such forms. The conflict between ovulists and animalculists was not only a scientific but also a social and even a theological affair. The ovulists stated that a female homunculus in an ovum contained ova, again with homunculi and so on. Therefore Mother Eva’s ovaries had contained ova in which all the coming human beings were present ,,generation packed in generation”. So the ovulists had a biological base for the doctrine of Preformation. A well known Dutch physician, who belonged to the ,,School of Animalculists”, was Herman Boerhaave. It was not till 1875, when Hertwig observed the nuclear fusion of sperm and ovum, that it became clear that the genetic contribution to a new human being comes from man and woman in an equal amount. Antoni van Leeuwenhoek’s spermatological studies lasted more than 40 years. Apart from human spermatozoa, he also described the spermatozoa of mammals, birds, amphibians, fishes, arthropods and moluscs. He demonstrated that the testis is the site of spermproduction and the epididymis the place, where the spermatozoa achieve their motility. He showed that the duration of motility of dog spermatozoa at room temperature in the seminal plasma, was 4-7 days. Contrary to the ideas of prominent scientists of the time, he adhered to hls opinion that the animalcules were a normal component of the semen and necessary for procreation. This conception familiar to us, was not acandrologia 11 (1979)
Early Development of Andrology
249
ceptable for many contemporaries of van Leeuwenhoek. It should last for about two centuries before van Leeuwenhoek’s conception was accepted in the whole scientific world. Even in 1844 the famous German physiologist Miiller stated, that the animalcules in semen were parasites! May it be that van Leeuwenhoek must share the place as discoverer of the spermatozoa with Johan Ham, the basical work in the foundation of Andrology was done by
him. Bibliography AUe de brieven van Antoni van Leeuwenhoek, uitgegeven, geillustreerd en van aantekeningen voorzien door een commissie van NEDERLANDSE Geleerden. Publisher: Swets en Zeitlinger, Amsterdam 1939-1967.
Address: Prof. Dr. J. Kremer, Parklaan 16, Groningen/The Netherlands.
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I
Gross, R. und P. Schoimerich (Hrsg.): Lehrbuch der inneren Medizin, 5., vollig neubearbeitete Auflage. Stuttgart: Schattauer 1977. LII, 1255 S . , mit 513 z.T. farb. Abb., 31 1 Tab. und 81 farb. Abb. auf 12 Tafeln. DM loo,-. Die 5. Auflage dieses bekannten Buches ist vollig neu uberarbeitet. Allein die Zahl der Abbildungen wurde u m ca. 20%, die Zahl der Tabellen u m ca. 50% erhoht. Dennoch gelang es den insgesamt 5 1 Fachleuten, ohne wesentliche Texterweiterung (etwa 10%) alle wichtigen neuen Daten in ihrem Sachgebiet iibersichtlich und umfassend darzustellen. Davon interessiert den Andrologen nicht nur das Kapitel von Bettendorf und Schirren, in dem ausfiihrlich auf die Erkrankungen der mannlichen und weiblichen Gonaden und speziell auf hormonelle Dysregulationen wahrend der Entwicklungs-, Reifungs- und Alterungsperiode des Organismus eingegangen wird. Denn auch in anderen Abschnitten dieses Buches werden andrologische Fragen beriihrt bzw. beantwortet; so z.B. die Fragen iiber Intersexualitat, insbesondere chromosomal bedingte MiDbildungen in dem Kapitel von Overzier sowie iiber Tumoren der mannlichen Genitalorgane in dem Kapitel von Hohenfellner und Altwin. Diese Kapitel enthalten in der gewunschten knappen Form alles wesentliche, was nicht nur der Student (auch nach der neuen AO) sondern jeder praktisch und klinisch tatige Arzt iiber das Fach Andrologie wissen m u & Auf alle weiteren Einzelheiten verweist die Literaturauswahl a m Ende der jeweiligen Kapitel. Die instruktiven Tabellen, Graphiken und Abbildungen erganzen den Text und sind wesentlich fiir die Empfehlung dieses Buches - speziell auch fur den andrologisch tatigen Arzt. Bei der hervorragenden Ausstattung ist der Preis angemessen. B. Schutte (Hamburg)
andrologia 11 (1979)
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