TOXICOLOGY AND PHARMACOLOGY 371 



theory of protective colloids. A priori we would be justified in be- 

 lieving that no difference exists between stabilized and unstabilized 

 metal hydrosol, but that a stabilization could be produced by the 

 dissolved albumins of the hashed organ or of the added blood. The 

 above example indicates the delicate adjustments in the mechanism 

 of colloid protection. [Different substances may compete for the 

 protector, thus establishing " preferential " protection. Tr.] 



It is interesting to note in addition, that the above investigators 

 found that minimal traces of prussic acid, mercuric chlorid and 

 cyanid, arsenious acid and carbonic oxid had as toxic an effect on the 

 autolytic action of silver hydrosol as upon its ability to split hy- 

 drogen peroxide. This process which was exhaustively studied by 

 G. BREDIG may be made to regress so that the metal hydrosols may 

 " recover." The identical observation was made by M. ASCOLI and 

 G. IZAR in respect to the autolysis by poisoned silver hydrosol. 



Blood: Hydrosols of silver, lead and mercury have the ability to 

 dissolve red blood corpuscles, whether the hydrosols are stabilized by 

 gelatin or not (M. ASCOLI #1 ). It is also interesting to learn that pure 

 powdered silver causes hemolysis, though this proceeds very slowly. 



The same silver powder when repeatedly used for hemolysis be- 

 comes inactive; serum inhibits hemolysis by silver. H. BECHHOLD l 

 observed that a drop of mercury causes strong hemolysis, which 

 serum did not inhibit. He also observed hemolysis with metallic 

 lead, though this was much weaker than in the case of mercury. 

 Metallic copper hardens the erythrocytes. 



Poisons do not interfere with the action of silver hydrosol. 



It is necessary in these effects to distinguish between the specific 

 activity of the metal involved and the generic activity due to the 

 development of surface. Hemolysis is induced by quite indifferent 

 suspensions, by kaolin (FRIEDBERGER and his pupils) as well as by 

 barium sulphate and calcium fluorid (O. GENGOU). Such hemolysis 

 is inhibited by serum. 



After ACHARD and E. WEILL, as well as A. ROBIN and E. WEILL, 

 had studied the influence of colloidal silver, and G. STODEL 2 had 

 studied the influence of colloidal mercury upon erythrocyte pro- 

 duction, E. FILIPPI, and later LE FEVRE DE ARRIC, carried these in- 

 vestigations further and extended them to other metal hydrosols. 

 The results in brief show that the red blood corpuscles are at first 

 diminished to a greater extent than the white. Later there is a con- 

 siderable increase of both red and white blood corpuscles. After the 



1 As yet unpublished. 



2 The fact that G. STODEL did not observe hemolysis of dog's blood with electri- 

 cally pulverized colloidal mercury is remarkable, and deserves further investigation. 



