364 Dynamic Theory. 



fully. Also by inserting the end of the tail under the skin near the 

 head, it grew there forming a handle to the animal, afterwards cutting 

 it in the middle there were two tails, and the new piece continued 

 thus to grow, and the nerves and vessels accommodated themselves to the 

 new direction of sensibility and nourishment. Siamese grafting or 

 joining two animals together was also effected by Bert. A slit is cut 

 on the side of two animals and the skin partly turned to face out; the 

 two animals are then sewed together with these strips, face to face. In 

 a few days the union is complete. Bert kept two white rats thus 

 joined for two months, but they quarreled so, he separated them. He 

 also thus joined a white rat to a Norway rat, and a white rat to a Bar- 

 bary rat. If one of such a brace be poisoned it effects the other like- 

 wise, showing the union of the circulation. The union of cats with rats, 

 and rats with guinea-pigs was also partly successful, and interrupted 

 rather by the uneasiness of the animals than the incongruity of the 

 tissues. 



Renewal of destroyed skin is very successfully accomplished by cov- 

 ering the part with strips or shreds of skin from other parts of the body 

 or from another person. Such grafts are generally complete in 24 

 hours. Even the skin of a guinea-pig has been successfully grafted on 

 a man. The epidermis in these graftings must be accompanied with 

 the sub-layer called the malpighian or color layer of the skin, as in the 

 epidermis alone the cells are too ripe. These facts prove that the es- 

 sence of vitality "does not depend on an indivisible spirit animating 

 the body ( mens agitat molem ), but on an activity distributed among 

 the minute particles that make it up, consubstantial with these particles 

 and as variable in its characteristics as they themselves are in their 

 structure. (Papillon.) In other words, "the total life of the individual 

 is but the sum, the resultant of the lives peculiar to each anatomical 

 element, the harmonious union of the simultaneous working of myriads 

 of monads the monads of Leibnitz gifted with life in different degrees 

 from the bony cell almost inert and mineral, to the nerve cell in which 

 a strong and fine fire burns unceasingly. " Every one of the living cor- 

 puscles is a complete entity in itself a simple animal reproducing by 

 fission. The fundamental character, the mark of life, is nutrition and 

 reproduction of cells. 



There can be no doubt of the unlimited susceptibility of modification 

 of organs and the disposition of the fundamental cells compatible with 

 life, especially when the modifying cause is applied to the embryo or to 

 the young. The same anatomical element shows the same composition 

 in all living species, in the lowest as well as the highest animal, which 

 is due to the fact that the nutritive materials are the same in all. The 

 first germs of life coming into contact with matter compatible with their 



