THE PROTECTIVE SUBSTANCES OF THE BLOOD. 371 



school now believes that the substances ordinarily foreign to the 

 organism, such as the indifferent narcotics, alkaloids, antipyretics, 

 antiseptics, do not effect a firm chemical union with the body ele- 

 ments, but that their distribution follows the laws of solid solutions 

 or of the formation of a loose salt. In the case of the poisons acting 

 on the central nervous system it is especially the fat-like substances 

 of the nerve tissue, the so-called lipoids, which take up the narcotics, 

 just as ether takes up the alkaloids in the Stas-Otto procedure of 

 detecting poisons. There are a number of reasons in support of the 

 view that the pharmacological agents in question are stored up un- 

 changed in the cells or in certain constituents thereof, especially in 

 those similar to tat. 



Naturally this does not deny the possibility that certain sub- 

 stances foreign to the body may enter an albumin molecule by sub- 

 stitution. Thus if protoplasma is treated with nitric acid the nitro 

 group enters the albumin radicle, giving rise to a yellow color. Such 

 substitutions, however, in the conditions under which pharmacolog- 

 ical actions can occur, will usually only be effected by combinations 

 possessing high internal tension and for that reason capable of such 

 addition reactions. This may perhaps be the case with vinylamin^ 

 which, according to Levaditi's experiments conducted in my labora- 

 tory, produces necrosis of the renal papillae in a large number of 

 animals, a phenomenon probably to be ascribed to such a chemical 

 anchoring. 



The ordinary medicinal substances, however, are not so constructed 

 that they can produce such energetic sections. In general we may 

 assume that chemo-synthetic processes do not play a prominent part 

 in their distribution. 



It may, however, be regarded as an absolute fact that synthetic 

 processes play an important role in the life of the cell in another 

 direction. If by boiling certain cell material with acids we are able 

 to split off certain definite groups (such as those of sugar, etc.), 

 this fact proves the chemical character of this combination. As a 

 matter of fact the two series of phenomena which we are here dealing 

 with have long been separated by general custom. The term assim- 

 ilability is reserved exclusively for those substances which are an- 

 chored by the cells synthetically, and which in this way become con- 

 stituents of the protoplasm. No one would think of speaking of 

 morphine, or of methylene blue, substances which enter into certain 

 cells and lodge there, as being assimilable. 



