Transformation, etc., of Pathogenic Microbes. 101 



of arresting their development. The number of the 

 antiseptics is quite considerable, but there are some 

 which stand at the top of the list and merit more es- 

 pecially the confidence of the practitioner. These are, 

 indeed, violent poisons for nearly all microbes, whilst 

 the others, less energetic, are only really efficacious 

 when they are directed against microbes the vitality 

 of which is easily destroyed. ISTevertheless, we can 

 not establish a general rule upon this subject; the 

 antiseptic action depends not only on the chemical 

 agent employed, but also on the microbe concerned; 

 it is also dependent upon the duration of contact, the 

 nature of the excipient, etc. The alcoholic solutions 

 of carbolic acid, for example, are less antiseptic than 

 aqueous solutions of the same concentration because 

 the former have a smaller power of penetration than 

 the latter. 



Antiseptic substances act either by rendering the 

 media unsuitable for the multiplication of the mi- 

 crobes, or by opposing themselves to the production 

 of the diastases indispensable to the elaboration of their 

 foods. 



We believe that it may be profitable to reproduce 

 here the classification of the antiseptics proposed by 

 M. Miquel. The antiseptic substances are here classi- 

 fied according to the dose of the substances necessary 

 for the sterilization of a litre of beef bouillon : 



1. The most jjowerful antiseptics : -01 to 0*1 gram. 

 (Oxygenated water, corrosive sublimate, nitrate 



of silver.) 



2. Very strong antiseptics : 0*1 to 1 gram. 

 (Iodine, bromine, sulphate of copper.) 



