THE NATURE OF TOXIN 



111 



TABLE 5 



Showing a specimen portion of the death record in greater detail 



pH 



Deaths. 



Alcoholic solution fatty acids: 



Incubation (days) 



Deaths 



Days to kill. 

 Deaths 



8.3 

 1 



8-12 

 4 



10-14 

 4 



There were included in these tables only those animals dying 

 without infection which presented at autopsy a definite picture 

 of the macroscopic lesions characteristic of death from diph- 

 theria toxin, viz., great emaciation, hemorrhages into the cap- 

 sules of the adrenals and kidneys, enlarged and hemorrhagic 

 kidneys, injection and hemorrhage of the lungs. Free fluid in 

 the pleural sacs and intestinal injection were variable signs. 

 The best results were obtained from dark colored broth inocu- 

 lated on the surface with 8 mgm. of the fatty acid antigen and 

 allowed to remain at 37°C. for five to six days, and which, at the 

 time of injection was clear, or with a fine colloidal haze, had a 

 pH of 7.9 to 8.1, a very slight or no surface pellicle and a slight 

 sediment consisting for the most part of crystalline phosphates. 

 Nearly all animals injected with such broth died. Filtration 

 through a Berkefeld filter greatly diminished the toxicity. 

 Distinctly cloudy fluids did not give good results. The antigen 

 in the form of the K salts gave good results, while no deaths at 

 all were obtained from the broth containing the ethyl, glyceryl 

 or cholesteryl esters. We found that with the same broth 

 inoculated with the same dose of antigen, in the same manner 

 so far as control was possible, there were obtained fluids of 

 many degrees of emulsification from clearness to dense cloudi- 

 ness. The reason for this in the absence of contamination was 

 not apparent. We had difficulty also in making different lots 

 of broth alike, particularly in color, some being pale, others dark, 

 depending somewhat on the quality of the veal used for making 

 the infusion. 



