MICRO-ORGANISMS BELONGING TO THE HIGHER BACTERIA 423 



In the earliest stages of its growth the parasite gives rise to a small 

 granulation tumor, not unlike that produced by the tubercle bacillus, 

 which contains, in addition to small round cells, epithelial elements 

 and giant cells. After it reaches a certain size there is great proliferation 

 of the surrounding connective tissue, and the growth may, particularly 

 in the jaw, look like, and was long mistaken for, osteosarcoma. Finally, 

 suppuration occurs, which, according to Israel, may be produced 

 directly by the fungus itself. 



The experimental production of actinomycosis in animals has been 

 followed by negative or very unsatisfactory results. When artificially 

 introduced into the tissues the organism is either absorbed or encap- 

 sulated. If introduced in large quantities multiple nodules are appar- 

 ently formed in some cases, which may suggest the production of a 

 general infective process; but on closer inspection of these nodules 

 the thread-like portion of the fungus is found to have disappeared, 

 leaving only the remains of the club-like ends, thus showing that no 

 growth has taken place. Ponfick, Johne, Rotter, Liming, and Hanan 

 claim to have obtained positive results in animals, but according to 

 Bostrcem these results are not conclusive. The animals used for experi- 

 mentation have been calves, swine, dogs, rabbits, and guinea-pigs, the 

 places of inoculation being the anterior chamber of the eye, the sub- 

 cutaneous intercellular tissue, the peritoneum, and the blood, and the 

 material employed for inoculation being pus from the infected regions 

 in animals and man, very rarely cultures. 



Streptothrix Infections. From widely scattered localities and at long 

 intervals of time reports have been published describing unique cases 

 of disease produced by varieties of micro-organisms belonging to 

 the genus Streptothrix. In some of these cases points of similarity 

 can be recognized in the clinical symptoms and the gross patho- 

 logical lessons, while others differ widely in both respects. They have 

 been found in brain abscess, cerebrospinal meningitis, pneumonic areas, 

 and in other pathological conditions. Eppinger injected cultures 

 into guinea-pigs and rabbits, and observed that it caused a typical 

 pseudotuberculosis. Consolidation of portions of both lungs, thicken- 

 ing of the peritoneum, and scattered nodules resembling tubercles, 

 were noted in a case of human infection as due to a Streptothrix by 

 Flexner, in which the pathological picture of the disease resembled 

 so nearly tuberculosis in human beings that the two diseases could be 

 separated only by the causative micro-organism in each case. But in 

 no two cases reported up to the present time have the descriptions 

 of the micro-organisms found agreed in all particulars. In some 

 cases no attempt at cultivation was made. In other cases numerous 

 and careful plants on various culture-media failed to develop the 

 specific organism. In the remaining cases in which the Streptothrix 

 was obtained in pure culture, the descriptions of the growth charac- 

 teristics essentially differ. In a recent review of the literature Tuttle 

 was able to find the reports of only twelve cases in which a Streptothrix 

 was found in sufficient abundance to have been an important, if not the 



