42 



SCIENCE 



[N. S. Vol. XLIII. No. 1098 



In France in the year of 1694, Nicholas 

 Hartsoeker claimed to have been the first 

 to have discovered the spermatozoa more 

 than twenty years previously, although he 

 did not publish until 1678, a year later than 

 Leeuwenhoek 's publication. Hartsoeker's 

 ideas are characterized by a high degree of 

 precision. He believes that each sperma- 

 tozoon conceals beneath its "tender and 

 delicate skin" a complete male or female 

 animal, "which would perhaps appear if 

 it could be seen like the following figure."' 

 The egg is merely a source of nourishment 

 for the real germ contained in the sperma- 

 tozoon. In birds the spermatozoon enters 

 an egg to be nourished; there is but a 

 single opening in the egg, situated over the 

 so-called germ, and this opening closes 

 after a single spermatozoon is admitted; 

 but if two spermatozoa enter they unite 

 and form a double monster. In mammals 

 the tail of the spermatozoon is the umbil- 

 ical cord; this unites with the ovum, i. e., 

 the placenta, and the latter with the uterus. 

 Each one of male animals (spermatozoa) 

 encloses an infinity of other animals both 

 male and female, which are correspond- 

 ingly small, and those male animals en- 

 close yet other males and females of the 

 same species, and so forth in a series which 

 includes all the members of the species 

 which are to be produced up to the end of 

 time. No difficulty was found in this con- 

 ception, for the atomic theory of matter 

 was not yet placed on a scientific basis. 



Thus was founded and flourished for its 

 brief day the school of the spermatists. 

 Unhampered by any scientific conception 

 of matter, living or non-living, there was 

 no obstacle to the eye of faith and no im- 

 pediment to the age-old longing to make 

 an intelligible universe out of the scraps 

 of experience. 



6 The figure in question is reproduced in Kelli- 

 cott's General Embryology, p. 22. 



The Period of Spallanzani. — In the en- 

 tire eighteenth century, although specula- 

 tion continued rife, there was only one 

 notable contribution to our subject. This 

 was the work of the Abbe Spallanzani, 

 "Experiences pour servir a I'histoire de 

 la generation des Animaux et des 

 Plantes," published in Geneva in 1785. 

 His working hypotheses were naturally in 

 the spirit of the times. Theories of repro- 

 duction, he says, may be reduced to two. 



The one explains the development of organisms 

 mechanically, the other supposes them to preexist, 

 and waiting only for fertilization to develop them. 

 The second system has given birth to two different 

 parties, one believing that the organism is pre- 

 formed in the ovum, the other that it is preformed 

 in the spermatozoon. 



Spallanzani believed that his observations 

 destroyed the epigenetic theory as pro- 

 pounded by Bulfon and others, because 

 they demonstrated the existence of the 

 fetuses (ova) in the females of toads, frogs 

 and salamanders, prior to the act of fertili- 

 zation, which according to the epigenesists 

 animates or creates the germ. For the 

 same reason the spermatists must also be 

 wrong. Spallanzani thus combated epigen- 

 esis as understood in the eighteenth cen- 

 tury, and also the ideas of the spermatists, 

 and he was led to deny that spermatozoa 

 are necessary for fertilization, and to hold 

 that the fertilizing power of the seminal 

 fluid resides not in the spermatozoa, but in 

 the fluid medium that accompanies them; 

 and this in spite of the fact that his final 

 experiments really proved the reverse. 



His work contains a great wealth of ob- 

 servation and experiment, so that it will be 

 possible merely to indicate some of his chief 

 results. In the first place he demonstrated 

 that in frogs and toads fertilization takes 

 place outside of the body, and for the first 

 time he successfully carried out artificial 

 insemination, thus laying the foundation 

 for the artificial propagation of many ani- 



