362 THE AMERICAN MONTHLY [Dec 



slight excess of ammonia, but not enough to cause any 

 annoyance. Neutralization of the formaldehyd occurs 

 very promptly, consequently only the few minutes neces- 

 sary for operating is consumed by this part of the process. 

 The formalin mixture used consists of 100 parts formalin, 

 20 parts calcium chloride fully dry, and 10 parts glycerin. 



CULTURES. 



The cultures employed were in each instance as near- 

 ly similar as it was possible to have them. The ty- 

 phoid and diphtheria were forty-eight hours old bouillon 

 cultures, and the anthrax was of several days growth — 

 old enough so that spores were always present. 



Small slips of sterile crash were moistened with the 

 culture, and those to be used in the dry state were allow- 

 ed to remain in a Petri dish, with the cover slightly raised, 

 at room temperature until the moisture evaporated; those 

 to be used wet were freshly prepared and no time given 

 for evaporation. Each slip was then wrapped in sterile 

 cheese cloth so that it was protected by about ten thick- 

 nesses. While the cultures were exposed under a variety 

 of conditions, they were always prepared in the same 

 manner. At the conclusion of each experiment they were 

 removed, the crash slips were placed in sterile bouillon 

 tubes and incubated at 37° C. for seven to twelve days. 



It was found that while the controls always grew in 

 twenty-four to forty-eight hours, the growth in many in- 

 stances in the other tubes seemed to be inhibited so that 

 development did not occur until the sixth or eighth day. 

 In all the experiments with anthrax alone the tubes were 

 incubated ten to twelve days. This particular organism 

 was very virulent,and in cases of doubt as to the growth, 

 mice were inoculated to decide the question. By combin- 

 ing dry heat and formaldehyd, better results odtaineb 

 than with the gas at ordinary temperatures. The degree 

 of heat and the quantity of formalin re<)uired for eJBBcient 

 work in a given space were not determined. 



