98 BACTERIOLOGY 



value of corrosive sublimate. In many bacteriological 

 laboratories it is the custom to keep at hand vessels con- 

 taining solutions of corrosive sublimate, into which infec- 

 tious materials may be placed. The value of this procedure, 

 as we have just learned, may be more or less questionable, 

 especially in those cases in which the substance to be disin- 

 fected is of a proteid nature and where the solution used is 

 not freshly prepared and frequently replenished. On the 

 introduction of such substances into the sublimate solution 

 the mercury is quickly precipitated by the albumin, and its 

 disinfecting properties may be in large part or entirely 

 destroyed; we may in a very short time have little else 

 than water containing an inactive precipitate of albumin 

 and mercury, in so far as its value as a disinfectant is con- 

 cerned. 



Though the other inorganic salts have not been so 

 thoroughly studied in this connection, it is nevertheless 

 probatle that the same precautions should be taken in 

 their employment as we now know to be necessary in the 

 use of the salts of mercury. 



The modes of action of other germicides have not been so 

 carefully investigated as has that of the metallic salts. 

 From the nature of many of them, however, we may infer 

 that some act through oxidation, as in the case of strong 

 acids and other active oxidizers; others by coagulation or 

 by dehydration, as in the case of strong aldehydes and 

 alcohols; and others by penetrating the cell wall and fatally 

 poisoning the bacterial protoplasm, as in the case of hydro- 

 cyanic acid and its compounds. 



Practical Disinfection. — ^Where it is desirable to use chemi- 

 cal disinfectants in the laboratory, much more satisfactory 

 results can usuall>' be obtained fropa the employment of 



