Waksman — 180 — Actinomycetes 



nomycosis was obtained in only 5, namely, progressive and fatal actino- 

 mycosis in 2 guinea pigs and in 1 rabbit, and localized and benign forms 

 in 2 other rabbits. Other repeated intravenous or intraperitoneal in- 

 jections of large doses of organisms seemed to be innocuous. Single 

 or repeated subcutaneous injection usually produced only mild local 

 lesions, from which the organism could seldom be reisolated. By intra- 

 pleural injection and by inclusion, in the inoculum, of sterile pulver- 

 ized salivary calculus, fatal reactions were obtained irregularly. 



The conclusion was reached that results thus obtained are in accord 

 with the view that actinomycosis is an endogenous infection. The 

 negative results frequently obtained in animal experiments appeared 

 to emphasize the function of unknown factors in the pathogenicity of 

 actinomycosis. Malignant actinomycosis could not be explained either 

 by repeated inoculation or sensitization. The concept of allerg)' to the 

 organism as a cause of progressive actinomycosis was eliminated. The 

 capacity of A. hovis to survive and multiply in the tissues was shown to 

 be of a very low order. The organism did not establish infection when 

 introduced in repeated massive doses by the intravenous or intraperi- 

 toneal routes; local lesions produced by subcutaneous inoculation under- 

 went rapid autosterilization. The occasional ability of the organism to 

 persist and proliferate in the tissues was believed to be conditioned by 

 as yet undisclosed factors of altered host resistance. 



The positive results obtained by Rosebury on inoculation of A. 

 hoxns mixed with sterile pulverized salivary calculus were believed to 

 embody direct evidence that this calcified deposit on the teeth may play 

 a part in the pathogenisis of actinomycosis. According to various in- 

 vestigators, including Naeslund, these masses contain A. hovis, which 

 seems to form the stroma upon which the masses are deposited. 



Actinomycetes of the A. Israeli type can be readily demonstrated in 

 broncho-pulmonary infections. In a study of 240 patients reported by 

 Kay (209), 109 cultures were isolated from the sputum, 65 from 

 bronchoscopic specimens, and 6 from long abscess exudates. The or- 

 ganism was believed to have less influence on the clinical course and 

 prognosis than the mechanical factors. 



Downing and Conant (94) also came to the conclusion that the 

 source of infection with A. hovis is endogenous. The fact that this 

 organism was isolated from tonsillar crypts and carious teeth have estab- 

 lished the human mouth as the habitat of this anaerobic species. They 

 recognized 4 types of actinomycosis: 



1. The cervicofacial type caused by A. hovis, probably the most frequent clini- 

 cal form of the disease. Tooth extraction or infection referable to the teeth is fol- 

 lowed by an infection through the tissues of the lower jaw and neck. Extensive 

 cellular infiltration of the lesion produces a tumor-like hard mass, from which ab- 

 scesses rupture, leaving multiple draining sinuses. Occasional extension of the 

 infection to the cranial cavity results in brain abscesses. 



2. Pulmonary actinomycosis is characterized by the chronic nature of the 



