STKEPTOTHRICOSIS. 453 



already noted the principal characteristics of this organism in both the text 

 and table in our first report and a summary is also shown in the table in this 

 one. Photomicrographic illustrations of its appearance in cultures are also 

 submitted. 



Morphologically this parasite shows marked variation under different environ- 

 ment. In young cultures and early lesions the hyphal forms are prevalent and 

 quite uniform in appearance, but in older cultures and in colonies from lesions, 

 irregularities are encountered. Coccus and bacillus-like forms predominate and 

 very old cultures may almost have the appearance of mixed culture of bacteria. 

 The filaments may or may not be radially placed at the periphery of the colonies. 

 There is true branching, but no true clubs have been seen in cultures or in 

 experimental lesions up to fifteen days of age. The Gram-Weigert method of 

 staining gives good results and portions acid fast to the Ziehl-Neelsen-Gabbett 

 method of staining are very numerous. The organism is also alcohol fast. 



Culturally this species is a facultative aerobe. It grows on the majority of 

 laboratory media at incubator or tropical room temperature ; development becomes 

 apparent in from two to four days after inoculation. The difficulty of securing 

 transplants from experimental lesions, mentioned in connection with S. madurce 

 does not obtain with this organism. The principal cultural characteristics on 

 various media are shown in the table and may briefly be summarized as follows : 



Small, white, irregular, round, raised, opaque colonies develop on ordinary 

 agar after two to three days. Growth is slow and not abundant and no pigment 

 is produced. 



Glycerine-agar after three days shows discrete colonies which coalesce later 

 and become heaped up, presenting a moist, meal-like growth. No pigment is 

 produced. 



On potato, growth appears after 4S hours as a buff-yellow, granular, raised 

 mass without pigmentation or erosion of this medium. 



■ In bouillon growth appears after 48 hours as a grayish, flocculent mass at the 

 bottom of the tube, later a few grayish granules appear on the surface of the 

 medium and in some instances "puffball" formations occur at the bottom of the 

 tube. The fluid remains clear. 



In ascitic fluid a very slight growth slowly develops at the bottom of the tube. 



In litmus-milk growth appears only at the bottom of the tube. The milk is 

 not coagulated and its color is not changed. 



Pathogenicity : This species is an exquisite tissue parasite for monkeys, and is 

 pathogenic to a less extent for some other animals. Monkeys inoculated in the 

 abdominal cavity and killed after five to fifteen days show characteristic lesions. 

 In the majority of instances the early lesions are tubercle-like formations scat- 

 tered through the mesentery and other tissues contiguous to the point of 

 inoculation. In some cases pus pockets and channels are formed, surrounded by 

 adhesions and containing granules made up of the microorganisms in the pus-like 

 material. Guinea pigs inoculated in a manner similar to the monkeys give 

 parallel results. 



No. 8. Streptothrix eppingeri "A," and 



No. 9. S. eppingeri "B." These strains are identical in all essential particulars 

 and may be described under the correct name of S. eppingeri. This is one of 

 the most important species of this group of organisms and has been well de- 

 scribed several times. It has been isolated from anatomical lesions of such 

 varying character as those from meningitis, by Eppinger and others, to Madura 

 foot, as has been published in our first report. Foulerton has described this 

 species and we have fully discussed its characteristics in our first report and 

 summarized them in the table in this paper. Our work has demonstrated fully 



