TOXICOLOGY AND PHARMACOLOGY 365 



The intravenous introduction of colloids has achieved great im- 

 portance through therapeutic use of colloidal metals (see below) . 

 Other apparently quite indifferent suspension colloids have a very 

 powerful action when introduced into the blood vessels. One or two 

 ccm. of a kaolin suspension injected intravenously into a guinea-pig 

 induce a violent reaction with more or less rapidly fatal termination. 

 FRIEDBERGEB and ISUNEOKA demonstrated that this could not be 

 attributed to embbli but that the toxic action depends on the adsorp- 

 tion of vitally important constituents of cells (analogous to the 

 destruction of blood corpuscles and bacteria in vitro, see p. 200). 

 "Sizing" the feet against chilblains and severe freezing is an ancient 

 household remedy which received renewed attention in the winter 

 campaign of 1914-1915. At present, there is no satisfactory explana- 

 tion of its action. [BAYLISS has recommended intravenous adminis- 

 tration of gum arabic solutions in shock to increase the blood pressure 

 after hemorrhage. DELAUNAY reports favorably on its use. Tr.] 



The peculiar effect of gelatin on the coagulation of blood is still 

 unexplained. In severe hemorrhages, purpura haemorrhagica and 

 hemophilia, gelatin is given internally (15 to 20 gm. daily) as well as 

 subcutaneously. Whether a colloid reaction occurs, or whether the 

 clotting of fibrin is favored by the calcium contained in the gelatin is 

 still an open question. 



Colloidal Metals. 1 



If we except the use of finely emulsified mercury in the form of 

 blue ointment, the introduction of colloidal silver by CREDE * in 1896 

 was the first instance of the employment of a colloidal metal because 

 of its colloidal nature. It was quite natural then to test other col- 

 loidal metals, mercury, gold, platinum, etc. The French have been 

 especially industrious in the study of the biological action of colloidal 

 metals (bibliography given by STODEL*), but the comprehensive in- 

 vestigations of the Italians, M. ASCOLI and G. IZAR* as well as E. 

 PHILIPPI* and PRETI,* anticipated them in showing that in all prob- 

 ability the action of inorganic hydrosols in their main features was 

 the same as that of the corresponding salts or of complex metal 

 salts. Salts with the cations concerned have in suitable, usually 

 very small, dosage, an effect similar to the action of the hydrosols. 

 This conclusion was demonstrated by the experiments of P. PORTIG * 

 as well as O. GROS and J. M. O'CONNOR,* but it was first placed on a 



1 A useful resume' of the methods of preparation and of the properties of col- 

 loidal metals may be found in TH. SVEDBERG, Die Methoden z. Herstellung 

 Kolloider Losungen anorganischer Stoffe (Th. Steinkopff, Dresden, 1910). The 

 older methods are contained in the little work of A. LOTTERMOSER, Anorganische 

 Kolloide (Ferd. Enke, Stuttgart, 1901). 



