The Message of Science. 73 



or ions from the brain cells through these cells it seems 

 well-nigh marvelous that this group (the germ-plasm) 

 should be so little affected, so little modified as Professor 

 Weismann would have us believe. 



Later researches afford indications that the intimate 

 causes of old-aging are resident, primarily, in the cell 

 nucleus. It has even been held by one observer that the 

 cell nucleus lives, individual and apart from its cell host, 

 originally intrusive and parasitic. But if so, it has be- 

 come so well domesticated as to participate naturally in 

 the life of the cell. 



The nucleus is found to be made up of a series of gran- 

 ules, composed of a substance chemically rich in phospho- 

 rus, to which the name of nuclein is given. These gran- 

 ules take aniline stains very readily, and are thus seen to 

 be connected one to another by the substance linine^ which 

 is not colored by the same dyes. Thus examined in old 

 and young cells, the quantity of nuclein in the latter is 

 found to be so uniformly greater in many instances that 

 the deduction is made that there is a progressive diminu- 

 tion of nuclein granules from youth to age, as the nucleus 

 divides, giving birth to new generations. As the nuclear 

 granules diminish, the somatic cell falls into senescence, 

 sinking to a condition where fission ceases. For a long 

 time it rallies and divides again, but produces an enfeebled 



