ATTENUATION OF ORGANISMS. 655 



energetic action in preventing putrefaction, whilst it does 

 not interfere with the activity of the digestive ferments. 

 According to Schulz and Hoffmann organic acids of the fatty 

 series, citric acid, formic acid, &c., are powerful antiputre- 

 factive substances ; formic acid in the amount of '25 per 

 cent, is able to preserve Bucholtz's nutrient fluid for months. 

 According to Donath* chinolin is antiputref active in the 

 percentage of '2, and according to Yigierforthophenolsulpho- 

 acid is active in a percentage of '5 to 1. Bert and Eegnard^ 

 have made experiments as to the antiseptic and disinfecting 

 properties of peroxide of hydrogen, and Chappuis on ozone, 

 but without paying sufficient attention to the dose of the 

 substance and the species of the bacterium. Kolbe || has 

 drawn attention to the fact that when kept in vessels filled 

 with carbonic acid fresh ox flesh can be preserved against 

 putrefaction for four to five weeks ; mutton cannot, however, 

 be similarly preserved. More accurate examination of the 

 antiseptic properties of carbonic acid is desirable. 



According to experiments by Kuisl^f potash soap is not 

 such a good inhibitory substance for other bacteria as for 

 anthrax bacilli. Even when present in a concentration of 10 

 per cent, it was not able to prevent putrefaction in meat. 



II. Attenuation of Pathogenic and Fermentative 

 Organisms. 



By noxious influences of definite but closely limited Attenuation 

 intensity we may so alter many bacteria that they lose 

 certain of their vital functions, this loss lasting for a 

 long time and even when the cultivation is continued 

 under completely normal conditions. The noxious 

 factors which are suitable for this action are less ener- 

 getic than those which cause complete death of the 

 bacteria; on the other hand, the effects are more marked 

 than in the case of the inhibitory means, which only 

 exert their action so long as they are present in the 

 nutrient substratum. At times, however, the greater 

 effect necessary for attenuation can also be produced by 

 sufficiently long-continued action of the milder means. 

 When properly regulated, high temperatures and various 



* Chem. Ber., vol. 14. t Mem. soc. biolog., 1884. 



J Compt. rend., vol. 94. Bull. soc. Chim., vol. 35. 



|| Journ.f.prakt. Chem., (2) vol. 26. 

 1 Munch, urztl. IntdligenzbL, 1885. 



