Morphology, Cultivation. 645 



tion and swelling of the external membrane of the filaments. (These 

 club-shaped ends may be entirely absent- when growth is prolific.) 

 When the conditions for development are unfavorable, granules of lime 

 salts are deposited in the colonies, sometimes also granules of iron 

 sulphate. 



The typical form of colony thus described which consists of a 

 central mass of filaments with a peripheral envelope or mantle, is 

 usually found well developed only in the actinomyces of human beings, 

 while those found in cattle usually consist in the main of masses of 

 club-shaped, swollen filaments. 



According to the investigations of Ligni^res & Spitz the property of forming 

 dichotomous filaments is characteristic of a number of species of bacteria which 

 may be referred to as actinophytes, while the diseases caused by their presence are 

 known as actinophytoses (See page 667). Among the actinophytoses we have 1. 

 the classic Actinomyces bovis or Streptothrix actinomyces ; 2. the Streptothrix 

 Israeli and 3. the actinobacillus. 



Staining. The filaments and spores stain readily by Gram's method 

 or by that of G-ram-Weigert. The club-shaped ends may be stained with 

 carmine, eosin, etc. 



Cultivation. The Ray fungus thrives on the usual artificial media 

 in the presence of oxygen, but only moderately so under anaerobic 

 conditions (cultures will not develop unless the colonies are crushed 

 and the detritus thus produced transferred to the culture medium). 

 On gelatin or agar, but still more iJeautif ully on coagulated blood serum, 

 it forms small points resembling dewdrop, which gradually become white 

 and project above the surface like buds. In gelatin they sink to the 

 bottom of the medium as a result of liquefaction of the latter. Sub- 

 sequently the granules assume a yellowish or reddish (the latter 

 especially in blood serum), occasionally also a decided brick red color, 

 are rather hard and, being provided with radical filaments they become 

 firmly attached to the bottom of the vessel; finally they become con- 

 fluent and form large, dry, wrinkled and prominently projecting 

 colonies. When not too thickly sown on potatoes they form grayish 

 granules which finally develop into prominent, pitted colonies with 

 crumpled borders and depressed centers, usually having a Sulphur 

 yellow, reddish-yellow or moldy color (Fig. 101), while on the other 

 hand, when the material is thickly sown, a continuous growth occurs 

 from 1 to 2 mm. thick, delicately folded on the surface, yellowish-gray 

 in the beginning, and later becoming reddish-yellow. In bouillon 

 whitish granules occur which form a membranous mass on the surface 

 of the fluid, or confluent masses imbedded in a slimy substance at the 

 bottom of the vessel, while the fluid itself always remains clear. In 

 fluid serum or in pleural exudate a capsule is formed around the fila- 

 ments (Wright). The Ray fungus will grow also on eggs, in sterilized 

 milk, in water and in other media. 



Tenacity. Cultures are quite resistant to the effects of drying; if kept at 

 ordinary room temperature they remain active for a year or more. The spores are 

 not destroyed by boiling for 14 minutes; 5% carbolic acid solutions are harmless 

 in their effect; corrosive sublimate solutions of 1:000 will kill them in five minutes 

 (Liebmann). Dry spores remain active for six years and withstand continuous 

 exposure to the sunlight for 238 hours (Berard & Nicolas). According to Nocard 

 the addition of 1% notassium iodide to the medium does not retard the develop- 

 ment of the fungus, but according to Eajewsky the addition of %% of potassium 

 iodide completely cheeks development. 



