Abstract
The brief vitality of many of the cultures of diplococcus intracellularis is a point of differential importance. Many strains, grown on a favorable medium, unless transplanted to a fresh 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° C, undergoes dissolution more rapidly and completely than a weaker suspension. The vitality of the cultures is associated with the degree of autolytic alterations in the suspensions: cocci in the weak suspensions survive longer than in the stronger ones. At lower temperatures — 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 concentrations, 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 ° 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.
Get full access to this article
View all access options for this article.