408 COLLOIDS IN BIOLOGY AND MEDICINE 



suffice to prevent multiplication or the infection of animals on the 

 part of the germs weakened by the antiseptic. " 



"Anthrax bacilli (HEINZ) like anthrax spores prior to the lethal 

 action show a stage of weakness in which the bacilli are unable to 

 grow in a nutritive medium containing a minimal amount of disin- 

 fectant. Thus anthrax bacilli which had been immersed in 1 per 

 cent carbolic acid (and had not been killed) did not grow in a culture 

 medium which contained a small amount of carbolic acid, " whereas 

 fresh anthrax bacilli grew luxuriantly. 



I find a very instructive example in OTTOLENGHI'S * paper. He 

 says, "The fact is very interesting, that occasionally certain paper 

 strips (he soaked blotting paper strips with an emulsion of anthrax 

 spores, dried them and then placed them in sublimate solution) after 

 they have been subjected for 24 hours to a sublimate solution (up to 

 2.712 per cent) and were inoculated into guinea pigs, may yield a 

 luxuriant development of anthrax bacilli if they are removed from the 

 thoroughly healthy animal after one week and are placed on media 

 after a thorough treatment with H 2 S. " The results of H. REICHEN- 

 BACH 1 are to be judged from the same standpoint. After tr eating- 

 anthrax spores with sublimate, they first lost their activity in the 

 bodies of animals, then their ability to grow in bouillon (without 

 ammonium sulphid treatment) and only after a much longer time 

 did they cease to grow, even after treatment with ammonium sulphid. 



Unquestionably numerous analogous examples would be found 

 were the literature carefully studied. 



It may be seen from this that in disinfection experiments, the 

 chemical removal of the disinfectant may lead to false results, that it 

 may simulate a weaker action of the disinfectant than it actually has, 

 i.e., a weaker action than it possesses in practice under natural 

 conditions. On this account I regard repeated washing of the germs 

 with indifferent solvents (water or physiological salt solution which 

 is finally made faintly alkaline with soda) as the proper method for the 

 removal of the disinfectant. Whatever is retained by the germ after 

 such a washing would also be retained under natural conditions. The 

 BECHHOLD-EHRLICH method of killing germs (see p. 406) meets all 

 these conditions correctly. 



This criticism relates to the testing of disinfectants against germs 

 which can directly enter the organism (disinfection of the hands, 

 antiseptics, etc.). It is otherwise with substances which serve 

 for the disinfection of stools, sputum, etc. Under these circumstances 

 we must consider that the disinfectants penetrate an environ- 



1 According to personal letter. See also H. REICHENBACH, Zeitschr. f. Hy- 

 giene und. Infectionskrankh., 60, 455, u. 460-462 (1905). 



