374 COLLOIDS IN BIOLOGY AND MEDICINE 



tions from J. VOIGT the silver is precipitated at the site of injection 

 after intramuscular injections and in the peritoneum after intra- 

 peritoneal injections, whence it is gradually transported to the internal 

 organs. It is still an open question whether the transportation is 

 purely mechanical or results from solution and reprecipitation. 



Therapeutics. 



It is obvious from the preceding statements that metal hydrosols 

 may, from very different causes, exert a therapeutic action. In in- 

 fectious processes we may imagine that there is a direct action on 

 the excitants of infection; although this may be due to an indirect 

 action inasmuch as the hydrosol stimulates the formation of anti- 

 bodies and phagocytosis, or it may injure the infecting organisms by 

 intensifying metabolic changes in some way. 



In view of G. BBEDIG'S experiments on the catalytic action of col- 

 loidal metals, a catalytic action of metal hydrosols which produces 

 effects similar to the ferments in the living organisms has been 

 frequently suggested. Personally, I prefer to leave undecided 

 whether such an expression as " catalytic action" has any real mean- 

 ing in this connection or whether it is nothing but an empty word. 



We shall merely mention here the experiments with colloidal mer- 

 cury, which has been chiefly used in syphilis and shows a specific 

 action similar to that of other mercury preparations. 



Animal Experiments. 



In the case of silver hydrosol there exist many experiments of 

 C. FOA and A. AGGAZZOTTI.* They infected rabbits with staphyl- 

 ococci and after an hour injected 30 cc. of a red silver hydrosol, 

 repeating this several times. In this way they delayed the death 

 of the animal from 1 to 3 days but recovery was not brought about. 



In infections with diplococci and typhoid (in dogs) the animals 

 could be kept alive with injections of silver hydrosols. In the latter 

 instance this was even possible when the silver-hydrosol injection 

 was given in doses of 5 cc. intraperitoneally as late as 12 to 24 

 hours after the injection of the microorganisms. 



The same authors found that silver hydrosol has no effect on 

 toxins in vitro, whereas it inhibits the toxicity if it is injected imme- 

 diately after the toxin. From this they concluded that silver hydro- 

 sol activates the oxidizing ferments of the body. 



CHARRIN, V. HENRI and MONNIER-VINNARD * speak very guard- 

 edly concerning their therapeutic results, and characterize them as 

 "very promising." CHIRIE and MONNIER-VINNARD* experimented 



