i4 Greek Biology 



An abler work than any of these, but exhibiting less power 

 of observation is a treatise, Trept yovfis, On generation, that may 

 perhaps be dated about 380 B. c. 1 It exhibits a writer of much 

 philosophic power, very anxious for physiological explanations, 

 but hampered by ignorance of physics. He has, in fact, the 

 weaknesses and in a minor degree the strength of his successor 

 Aristotle, of whose great work on generation he gives us a fore- 

 taste. He sets forth in considerable detail a doctrine of pan- 

 genesis, not wholly unlike that of Darwin. In order to explain 

 the phenomena of inheritance he supposes that vessels reach the 

 seed, carrying with them samples from all parts of the body. 

 He believes that channels pass from all the organs to the brain 

 and then to the spinal marrow (or to the marrow direct), 

 thence to the kidneys and on to the genital organs ; he 

 believes, too, that he knows the actual location of one such 

 channel, for he observes, wrongly, that incision behind the 

 ears, by interrupting the passage, leads to impotence. As an 

 outcome of this theory he is prepared to accept inheritance of 

 acquired characters. The embryo develops and breathes by 

 material transmitted from the mother through the umbilical 

 cord. We encounter here also a very detailed description of 

 a specimen of exfoliated membrana mucosa uteri which our 

 author mistakes for an embryo, but his remarks at least exhibit 

 the most eager curiosity. 2 



The author of this work on generation is thus a ' biologist ' 

 in the modern sense, and among the passages exhibiting him 

 in this light is his comparison of the human embryo with the 

 chick. * The embryo is in a membrane in the centre of which 

 is the navel through which it draws and gives its breath, and the 



1 The three works nep\ yovr)s, rrep\ (pvcrios Traifiiov, 7Tfp< vovcratv d', 

 On generation, on the nature of the embryo, on diseases, book IV, form 

 really one treatise on generation. 



2 Trepi (f)v(rios naio'iov, On the nature of the embryo, 13. The same 

 experience is described in the Trepi (rap/ccoy, On the muscles. 



