22 GENERAL ANATOMY. 



The solidity of different fats depends upon the proportional quantity of the 

 above-mentioned substances. A preponderance of Elain renders the fat fluid, 

 such as oils ; Margarin constitutes the solid element of lard, whereof human 

 fat is an example ; Stearin of suet. 



II. ELEMENTARY FORMS OF THE HUMAN BODY. 

 a. Elementary parts. 



13. The first form from which matter is developed, and which 

 lies as the basis of every organic structure (vegetable and animal), 

 is, according to the general principle first enunciated by Schwann, 

 1838, the 



Nucleated Cell, that is, a microscopical, delicately membranous vesicle, with 

 fluid contents and a minute dark nucleus (Cytoblast) in one of its walls, sur- 

 rounded by an amorphous, solid or fluid, substance (Cytoblastema or Inter- 

 cellular substance), out of which the nucleated cell forms itself. 



The nucleus is round or oval, rather flattened, yellowish red, smooth or 

 granular, has a diameter of 0*002 0'004 W and probably first arises, as the 

 granules are deposited from the amorphous mass about a central point, are 

 circumscribed and blend together. About the nucleus formed from the mass 

 a membrane is generated, the vesicle of the cell [cell membrane]. 



14. This process of development may at least be observed in 

 the egg [germ] of vegetables and animals, in the formation and 

 reproduction of certain tissues (for example, the nails and cuticle). 

 Also in the blood, in pus, and in milk, the process is essentially 

 the same. The formation of the elementary granules may be 

 compared with the physical phenomenon, discovered by Ascher- 

 son, namely, that when albumen was brought into contact with 

 fat (oil drops) it coagulated in the form of a membrane, and 

 enveloped them. But the vital and self-dependent progressive 

 development of the nucleated cell is in no degree explained by 

 this. 



15. Increase of the Cells. The number of the cells in a 

 tissue in the process of development, increases either by the 

 origin of single new ones independent of one another (e. g., in the 

 hair, nails, inflammatory exudation) ; or by the development, in 

 the interior of the old and mature, of new secondary cells, to 

 which the contents of the primary cell serve as cytoblastema. 

 (Thus, in the development of the liver, and in pathological 

 growths; e. g., Scirrhous.) 



16. Metamorphosis of Cells. As the cells pass through vari- 

 ous stages of development, they also present different circum- 

 stances in respect to their shape, position, contents, and chemical 

 relations. In some tissues they maintain their independence, at 

 most lying upon one another, and becoming thereby flattened, or 



