106 GERMICIDAL PBOPERTIES OF BLOOD SEBUM. 



temperature, is still capable of destroying from 35,000 to 40,000 

 typhoid bacilli within four hours. 



It is possible that the more powerful action of the solution made 

 by Christmas is due to the presence of the germicidal substance in 

 more nearly a chemically pure condition than it exists in blood 

 serum, and later we shall see that the temperature at which the 

 germicidal activity of blood serum is arrested is variable, and de- 

 pends upon conditions which are not thoroughly understood. 



Attempts have been made to determine the nature of the germi- 

 cidal constituent by the action of precipitating reagents on the pro- 

 teids of blood serum. Buchner was not able to obtain a germicidal 

 solution by precipitating all the proteids with absolute alcohol, free- 

 ing the precipitate from alcohol, drying it, and then redissolving it. 

 Inasmuch as he failed to give the methods employed in freeing the 

 precipitate from alcohol, the temperature or the conditions under 

 which it was dried, and the nature of the menstruum by which re-so- 

 lution was effected, his conclusion that alcohol destroys the germi- 

 cidal substance must remain open to question. On the other hand, 

 Christmas found that when the proteids are precipitated with alcohol 

 and the precipitate dissolved in a volume of water equal to that of 

 the original solution, the solution thus obtained has a more powerful 

 germicidal action than the serum. 



Bitter reached the conclusion that anthrax and typhoid bacilli are 

 destroyed by " precipitated serum," but not so energetically as by 

 normal serum. Emmerich, Tsuboi, Steinmetz and Low studied the 

 effect of precipitation of the proteids upon the germicidal properties 

 of the blood serum. An active serum was dialyzed in a sterilized 

 parchment paper tube against water for from twelve to eighteen 

 hours. By the expiration of that time the serum globulin, becoming 

 insoluble on account of the withdrawal of inorganic salts, was depos- 

 ited. The dialyzer was dried with sterilized filter paper, and the 

 globulin-free serum was precipitated with several volumes of alcohol. 

 The precipitate was collected on a sterilized filter and the alcohol 

 removed by sterilized porous plates and filter paper. The precipi- 

 tate was then finely divided, dried for half an hour in vacuo at 36°, 

 then rubbed up in a sterilized mortar and dissolved in sterilized 

 water, to which salt solution had been added. In the solution thus 

 prepared germs did not show, after from three to four hours, either 

 a marked increase or decrease, but when the solution was heated to 

 100°, allowed to cool, and then inoculated with germs, the increase 

 was four hundred-fold within four hours. It was next found that if 

 instead of water a 0.05 per cent, aqueous solution of potassic hydrate 

 was employed in dissolving the alcoholic precipitate in the globulin- 

 free serum, this solution possessed all the germicidal strength of the 

 original serum. The same was found to be true of dilute alkaline 

 solutions of the alcohol precipitate in serum from which the globulin 



