482 MUSGRAVE, CLEGG, AND POLK. 



by means of continuity, but more usually by intercommunicating channels 

 running in various directions. These channels contain the broken down 

 tissue and granules made up of colonies of the infecting organism. Few 

 tissues escape the destructiveness of the Streptothrix, but it appears to be 

 more active in the connective tissues, bones, and mucous membranes. 

 However, practically every organ and tissue of the body has been involved. 

 The disease spreads through the body in at least two ways, by directly 

 continuing along the tissues, in which case the area involved is rarely 

 great, and by metastases through the blood vessels, when the infection 

 may be so great as fairly to be considered a general infection. 



The character of the morbid process suggests that the minute action 

 is toxic in character, although if such is the case, the toxin must act 

 very slowly. The lymphatics near a diseased process may be enlarged, but 

 are rarely found to be broken town or to contain the microorganism. 



Symptoms. — The clinical manifestations of Streptothrix infections are 

 essentially those of a slowly developing, chronic inflammatory process. 

 They vary much with the location of the lesions and further complications 

 are secured by the presence of mixed infections which are frequent when 

 the disease attacks regions of the body exposed to bacterial invasion. 

 In many instances, where the lesions are located in the internal organs 

 such as the liver, definite clinical manifestations do not occur and unless 

 the infection spreads, its nature in all likelihood is not recognized during 

 life. 



When the lesions are located externally, or in places where the dis- 

 charges reach the surface of the body, the nature of the infection should 

 be suspected from the appearance of the wound and the character of the 

 discharges; on the other hand, it may be generalized, manifest itself in 

 an acute course and be difficult to distinguish from a pyaemia" of other 

 etiology. 



The incubation period varies between wide limits, and as given by 

 authors may be from a few days to more than two years. The onset 

 is usually gradual, by the slow development of the lesions. 



The following clinical varieties may be recognized: 



Generalized streptothricosis. — This form of infection has been noted 

 by several observers. It occurred 9 times in Ackland's 109 cases. 

 This type usually begins in a local lesion and is transmitted through the 

 blood vessels. In the majority of instances, it occurs in mixed infections 

 with bacteria, but cases in which no bacteria were present have also been 

 reported. Several species of the organisms causing these general infec- 

 tions have been found. This type is generally acute or subacute clinically 

 and the symptoms as given by various authors are similar to septicaemia 

 or pyaemia from other causes. Extensive lesions may occur in practically 

 every organ and tissue of the body. The diagnosis is only made by- 

 laboratory methods, the prognosis is bad and treatment unsatisfactory. 



Thoracic streptothricosis. — The organs of the chest, particularly the 



