40 



SCIENCE 



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



help to justify our faith, and also to tem- 

 per our conceit, if we have any. Fertiliza- 

 tion is such a central problem which has 

 interested mankind from the dawn of 

 reasoning on account of its fundamental 

 character, and is more or less interwoven 

 with the thought of all ages. 



Aristotle and Harvey. — It must be re- 

 membered in beginning our topic that the 

 problem of fertilization was not clearly 

 separated from the general problem of re- 

 production until well into the nineteenth 

 century. In early human culture repro- 

 duction received its only iaterpretation at 

 the hands of priests and mystery men; its 

 first philosophical and scientific treatment 

 was one of the great distinctions of the 

 Greeks, especially of that great philosopher 

 and father of science, Aristotle, who com- 

 bined observation and reflection in the in- 

 terpretation of nature. Aristotle devoted 

 a separate treatise, which has come down 

 to us, to animal reproduction. Among 

 other things he studied the development of 

 the chick day by day with so much detail 

 that Harvey felt impelled to say, 1,900 

 years later : 



Aristotle among the ancients, and Hieronymus 

 Fabricius of Aquapendente, among the moderns, 

 have written with so much accuracy on the gen- 

 eration and formation of the chick from the egg 

 that little seems left for us to do. 



From the time of the Greeks to that of 

 Harvey (1651) there was but little prog- 

 ress in the knowledge of reproduction, and 

 none in the theory, as will appear from the 

 views of Aristotle, the current views of 

 medical men of Harvey's time, and of 

 Harvey himself. Aristotle says:^ 



The male is the efficient agent, and by the mo- 

 tion of his generative virtue (genitura), creates 

 what is intended from the matter contained in the 

 female; for the female always supplies the mat- 



2"De Gen. Anim.," lib. II., cap. 4, quoted 

 from Harvey ' ' On the Generation of Animals, ' ' 

 Ex. 29. 



ter, the male the power of creation, and this it is 

 which constitutes one male, another female. The 

 body and the bulk, therefore, are necessarily sup- 

 plied by the female; nothing of the kind is re- 

 quired from the male; for it is not even requisite 

 that the instrument, nor the efficient agent itself, 

 be present in the thing that is produced. The 

 body then proceeds from the female, the vital 

 principle (anima) from the male; for the essence 

 of every body is its vital principle (anima). 



With more common sense, if with less 

 metaphysical subtlety, the physicians of the 

 Middle Ages held, according to Harvey, 

 that conception is due to a mingling of 

 male and female seminal fluids, 

 the mixture having from both equally the faculty 

 of action and the force of matter; and according 

 to the predominance of this or that geniture does 

 the progeny turn out male or female (quoted from 

 Harvey, Ex. 32). 



Harvey's observations contained much 

 that was new and significant, but the facts 

 that he knew were inconsistent both with 

 Aristotle's ideas and those of the physi- 

 cians. They were, however, inadequate for 

 sound generalization. 



Wandering between two worlds, one dead 

 The other powerless to be born, 

 he descended deeper into the slough of 

 metaphysics than Aristotle, and committed 

 himself to the fantastic idea that concep- 

 tion in the uterus is identical with, or at 

 least analogous to, conception in the brain ; 

 and that the ovum is the product of such 

 unconscious uterine desire or conception, 

 and receives no material substratum from 

 the male !^ The theory of reproduction 



3 ' ' Since there are no manifest signs of concep- 

 tion before the uterus begins to relax, and the 

 white fluid or slender threads (like the spider's 

 web) constituting the 'primordium' of the future 

 ' conception ' or ovum, shows itself ; and since the 

 substance of the uterus, when ready to conceive, is 

 very like the structure of the brain, why should we 

 not suppose that the function of both is similar, 

 and that there is excited by coitus within the 

 uterus a something identical with, or at least 

 analogous to, an 'imagination' (phantasma) or a 

 'desire' (appetitus) in the brain, whence comes 



