THE CHEMICAL UNITY OF LIVING BEINGS. lOI 



diate principles highest in complexity among those 

 which form the living protoplasm. We must analyze 

 the two components, the albumins and the histones on 

 the one hand, and the nucleins on the other. As for 

 the nucleins, this has already been done, or very 

 nearly so. 



Kossel, in fact, decomposed the nuclein by a series 

 of very carefully arranged operations, and has reduced 

 it step by step to its crystallizable organic radicals. 

 At each stage that we descend in the scale of 

 simplification a body appears which is more acid and 

 more rich in phosphorus. At the third stage we 

 come to phosphoric acid itself The first operation 

 divides the nuclein into two substances: the new 

 albumin and nucleinic acid. After separating these 

 elements they can be reunited : a solution of albumin 

 with a solution of nucleinic acid reconstitutes the 

 nuclein. A second operation separates the nucleinic 

 acid in its turn into three parts. One is a body of 

 the nature of the sugars — i.e., a carbohydrate. The 

 appearance of a sugar in this portion of the molecule 

 of nucleinic acid is an interesting fact and fertile in 

 results. The second part is constituted by a mijcture 

 of nitrogenous bodies, well known in organic chemistry 

 under the name of xantJiic bases (xanthin, hypo- 

 xanthin, guanin, and adenin). The third part is a 

 very acid body and full of phosphorus — thymic acid. 

 If in a third and last operation the thymic acid is 

 analyzed, it is finally separated into phosphoric acid 

 and into thymene, a crystallizable base, and thus we 

 arc brought back to the physical world, for all these 

 bodies incontestably belong to it. 



