Scientific Proceedings. 



27 



medium, do not survive beyond two or three days. Cultures three 

 days old show marked degenerations, and the latter increase 

 rapidly with age until, at the end of five or six days, or even earlier, 

 no normal cocci persist. As degeneration progresses, loss of 

 staining power and disintegration ensue, until finally, staining 

 capacity is lost and a formless detritus remains. 



The changes in the diplococcus are associated with the action 

 of an enzyme which brings about the disintegration. This enzyme 

 does not exhibit the usual properties of a proteolytic ferment : it 

 does not liquify gelatin or coagulated serum. The degree and 

 rapidity of its action varies with its concentration ; at least a heavy 

 suspension of the cocci in salt solution, kept at 37 0 C, undergoes 

 dissolution more rapidly and completely than a weaker suspen- 

 sion. The vitality of the cultures is associated with the degree 

 of autolytic alterations in the suspensions : cocci in the weak sus- 

 pensions survive longer than in the stronger ones. At lower tem- 

 peratures — 2°C. — disintegration of the cocci either does not take 

 place at all or progresses much more slowly. Under the latter 

 conditions more cocci survive in the strong than in the weak con- 

 centrations, although even here the vitality is a brief one. 



Potassium cyanide restrains the action of the ferment which 

 tends to disintegrate the diplococci ; after removal of the cyanide, 

 dissolution sets in. Heating the diplococci to 65 0 C. prevents or 

 reduces the dissolving power of the intracellular enzyme. 



The brief vitality which the diplococcus exhibits, as grown 

 upon the usual media, and in salt suspensions, is associated with a 

 deficiency of calcium in the media. If the diplococcus is sus- 

 pended in Ringer's solution it survives, in concentrated suspen- 

 sions, for 15 days at least, and if it is grown upon serum-glucose- 

 agar to which calcium carbonate has been added, the period of 

 viability is considerably greater than this. The diplococcus sus- 

 pended in Ringer's fluid and killed by heat (6o° C.) or toluol, 

 undergoes autolysis. 



The enzyme acts upon the dead cocci — probably not upon the 

 living germs. Diplococci killed by heat (50 0 to 55 0 C.) undergo 

 autolysis ; but when the cocci are killed by the addition of toluol 

 autolysis is accelerated. A heavy suspension of the diplococci in 

 salt solution, under toluol and kept at 37 0 C, may be disintegrated 

 in four hours. 



