6 READINGS IN BIOLOGICAL SCIENCE 



according to a regimen inclined to fire. And not only must the man do 

 this, but also the woman. For growth belongs, not only to the man's 

 secretions, but also to that of the woman, for the following reason. Either 

 part alone has not motion enough, owing to the bulk of its moisture and 

 the weakness of its fire, to consume and to solidify the oncoming water. 

 But when it happens that both are emitted together to one place, they 

 conjoin, the fire to the fire and the water likewise. Now if all the fire fall 

 in a dry place, it is set in motion, if it also master the water emitted with 

 it, and therefrom it grows, so that it is not quenched by the onrushing 

 flood, but receives the advancing water and solidifies it on to what is there 

 already. But if it fall into a moist place, immediately from the first it is 

 quenched and dissolves into the lesser rank. On one day in each month it 

 can solidify, and master the advancing parts, and that only if it happen 

 that parts are emitted from both parents together in one place. 



EXCERPTS FROM Dc Generatioiie Ajiimalium * 

 (on the generation of animals) 



ARISTOTLE 



Now some animals come into being from the union of male and female, 

 i. e. all those kinds of animals which possess the two sexes. This is not the 

 case with all of them; though in the sanguinea t with few exceptions the 

 creature, when its growth is complete, is either male or female, and though 

 some bloodless animals have sexes so that they generate offspring of the 

 same kind, yet other bloodless animals generate indeed, but not offspring 

 of the same kind; such are all that come into being not from a union of 

 the sexes, but from decaying earth and excrements. To speak generally, if 

 we take all animals which change their locaHty, some by swimming, others 

 by flying, others by walking, we find in these the two sexes, not only in 

 the sanguinea but also in some of the bloodless animals; and this applies 

 in the case of the latter sometimes to the whole class, as in the cephalopoda 

 and Crustacea, but in the case of insects only to the majority. Of these, 

 all which are produced by union of animals of the same kind generate also 

 after their own kind, but all of which are not produced by animals, but 

 from decaying matter, generate indeed, but produce another kind, and 

 the ofl^spring is neither male nor female; such are some of the insects. 



But all those creatures which do not move, as the testacea and animals 



* From The Basic Works of Aristotle, edited by Richard McKeon, section trans- 

 lated by Arthur Piatt, by permission of Oxford University Press, New York. Copy- 

 right 1 94 1. 



t Animals with blood. — Ed. 



