40 PHYSICOCHEMICAL PROPERTIES 



undergo a series of successive transformations without the 

 whole of the injected product ever being able to take part 

 simultaneously in each of the reactions which follow. We 

 may outline this transformation in a schematic method as 

 follows : 



1. One part of the injected product, the more colloidal, 

 combines with the calcium salts, loses its sodium and thus 

 becomes rapidly an insoluble base of which one part continues 

 to circulate in the blood, while the other part is taken up by 

 leukocytes in the liver, the spleen, the lymphatic glands and 

 finally in the local lesions which become the site of an inflam- 

 matory process at the point of injection. 



2. Another part of the product is not precipitated and 

 continues to circulate in the blood as a sodium compound. 

 This is probably the least colloidal part. It can traverse 

 certain membranes and thus penetrate to the interior of cells 

 where it is fixed as a base; that is to say, as a new insoluble 

 compound. 



3. A third part finally becomes rapidly and almost simul- 

 taneously a base and a salt and as such may be partially 

 assimilated, that is to say, fixed by certain cells, partially 

 eliminated by the kidneys and intestines. In point of fact, 

 some minutes after the injection, traces of arsenobenzene 

 are found in the urine, to be sure in a soluble state, because 

 when one adds directly to the same urine a little of the 

 same solution of arsenobenzene there immediately forms an 

 abundant precipitate. The product has thus passed into the 

 urine in the form of a compound which is no longer precipi- 

 tated by salts. 



The proportion of the product which is either engulfed by 

 leukocytes as a precipitate, or which continues to circulate 

 in the blood as a precipitate or which passes out and precipi- 

 tates in the cells of different tissues as a colloidal solution or 

 as a salt and finally the proportion which is immediately 

 eliminated, vary widely according to the injected doses, 

 the degree of alkalinity of the product, and the composition 

 of the blood of the injected animal at the time of the primary 

 injection (or later if injections are made in series). Thus 

 symptoms may vary infinitely. 



