26 METAMORPHOSES OF MAN 



CHAPTER IV. 



TRANSFORMATIONS WHICH THE MAMMAL UNDERGOES 

 WITHIN THE EGG CELL THEORY. 



Having seen what occurs to the mammalian egg 

 and its coverings,, we shall now return to the embryo, 

 bearing in mind, that though the various organs of 

 which the body is composed unite in discharging one 

 grand function — life, — yet each individual apparatus 

 has its own particular part to play also. One set of 

 structures is connected with animal life, the other 

 with that series of phenomena common to animals and 

 plants, and hence termed vegetal ; whilst both derive 

 their support from a nutritious fluid — the blood — which 

 is borne to every tissue in the body by special canals, 

 termed arteries and veins. Here, then, we have three 

 distinct systems and organs ; what do they arise from ? 

 From the three folds or leaflets of the germinal area, 

 which we have described elsewhere. 



The external or upper leaflet develops the organs 

 of thought, sensibility, and motion; or, in other 

 words, the brain, spinal cord, nerves, bones, and 

 muscles, whose operations are controlled by the will. 

 The internal or lower fold produces those organs, 

 such as the digestive canal and its appendages, whose 

 functions, though of the greatest import, are per- 

 formed without our being conscious of them. Finally, 

 the heart, veins, and arteries, are developed from 



