AN ACTINOMYCES ISOLATED FROM MAN. 171 



cultures on 2 per cent, glucose, glycerin and plain agar present the same 

 general characteristics, save that the growth is most abundant on glu- 

 cose, less so on gljcerin, and least on plain agar. The time necessary 

 for the production of growth is usually not less than three days. 



Gelatine stabs develop slowly at 21°-22°, and not abundantly. After 

 a variable interval of 3-6 days, discrete colonies may appear along the 

 line of inoculation with a more profuse surface growth. The individual 

 colonies present a puff-ball appearance, consisting of a dense orange 

 center, surrounded by a peripheral radiating zone of a pale yellow color. 

 A surface film forms, due to the coalescence of adjacent colonies.. The 

 organism produces a strongly proteolytic enzyme. Unless grown in a 

 moist chamber, no liquefaction is at first observed owing to evaporation, 

 merely a retraction of the surface of the medium. Later, however, 

 fluidity of the medium occurs. When cultures are grown in the moist 

 chamber, however, liquefaction is apparent in two or three days and co- 

 alesced groups of colonies are seen floating on the surface of the fluid medi- 

 um. The liquefaction becomes cylindrical, and the floating mass of growth 

 may sink to the level of the underlying solid medium. Total liquefaction 

 'of the medium does not occur in several months. When portions of growth 

 are firmly streaked on gelatine j)lates, and the plates are developed in 

 a moist chamber at 22°, the medium about the implanted material be- 

 comes pitted, resulting in well-marked liquefaction in 24-48 hours, where- 

 upon the growth is observed as islands floating in the surrounding fluid 

 medium. In the course of a few days the whole plate becomes liquefied. 

 Proliferation does not seem necessary to the production of liquefaction, 

 as the transferred material alone possesses sufficient proteolytic power 

 to render fluid the surrounding medium, before further growth is ap- 

 parent. The liquefied medium does not become pigmented. A slight 

 pigmentation, however, was observed in the case of a single culture 

 about two months old. Free access of oxygen is evidently necessary to 

 the production of the enzyme, as deeply situated colonies do not appear 

 to possess this liquefying property. 



The proteolytic property of the organism is also markedly manifested 

 in cultures on Loeftier's blood serum. The growth here is very abundant 

 and rapid. The deep orange color manifested in cultures on other media 

 is modified by a brownish tint. The medium at first becomes pitted be- 

 neath the growth, and after three to six days marked liquefaction re- 

 sults. The medium becomes a clear, brown fluid, with a brownish sedi- 

 ment of the growth. 



Cultures in the glycerin bouillon and in plain bouillon are obtainable 

 and show on the bottom discrete colonies presenting a puff-ball appear- 

 ance, or a fluffy sediment, with individual colonies adherent to the sides 

 of the tube. The uppermost colonies having free access of air, are of a 

 deeper orange tint than the ones w^ell immersed in the liquid. The 

 medium remain perfecti}' clear. 



The numerous attempts which have been made to obtain a growth on 

 potato have been almost invariably unsuccessful, although a number of 

 modifications of potato media have been employed. With the potatoes in 

 Roux tubes containing alkaline pepton water a good growth can be 

 obtained. 



Cultures in litmus milk, containing 0.5 per cent, of N NaOH produce 

 an orange colored surface growth. No change occurs in the reaction of 



