THE CELLULAR CHANGES OF AGE 43 



in your minds until the final lecture, in which we shall 

 make practical use of our acquaintance with it. It is 

 unnecessary for our purposes to enter into a detailed 

 description of the complicated processes of cell di- 

 vision. But let me point out to you that the end result 

 is that where we have one cell we get as the result of 

 division two ; but the two divided cells are smaller 

 than the mother cell and have smaller nuclei. They 

 will, however, presently grow up and attain the size 

 of their parent. 



Every cell is a unit both anatomically and physio- 

 logically. It has a certain individuality of its own. 

 In many cases cells are found to be isolated or sepa- 

 rated completely from one another. But, on the other 

 hand, we also find numerous instances in which the 

 living substance of one cell is directly continuous 

 with that of another. When the cells are thus re- 

 lated, we speak of the union of cells as syncytium. 

 Of this I offer you an illustration in the second picture 

 upon the screen (Fig. 8), which represents the em- 

 bryonic connective tissue of man. In this you can 

 see the prolongations of the protoplasm of a single 

 cell body uniting with the similar prolongations from 

 other cell bodies, the cells themselves thus forming, 

 as it were, a continuous network with broad meshes 

 between the connecting threads of protoplasm. The 

 spaces or meshes are, however, not entirely vacant, 

 but contain fine lines which correspond to the exist- 

 ence of fibrils, which are characteristic of connective 

 tissue, and at the stage of development represented 



