DISEASES OF UNKNOWN ETIOLOGY 437 



Mumps. Herb has implicated a diplococcus. Inoculations into 

 Stenson's duct of monkeys successful. 



Rabies. Probably the Negri bodies. 



Roetheln (German Measles). Nothing known. 



Scarlet Fever. Streptococci seem most probable cause (S. anginosus). 

 Mallory has implicated epithelial protozoa. 



Dohle has reported the rather constant finding of basophilic round or oval inclu- 

 sion bodies in the polymorphonuclears. These findings, which are brought out in 

 stained films, are present only during the first few days of the attack of scarlatina. 

 Other workers have found these bodies almost as constantly present in diphtheria 

 as in scarlet fever. They have also been found in other acute diseases than diph- 

 theria. Klemenko has obtained streptococci from the blood in only about 2% of 

 cases of scarlatina. Quite recently Mallory has reported diphtheroid organisms 

 as the cause. 



Smallpox and Vaccinia. Guarnieri and Councilman have impli- 

 cated epithelial protozoa. 



Spotted Fever of the Rocky Mountains. Supposed to be due to an 

 unknown protozoon transmitted by a tick, D. andersoni. 



This disease is especially prevalent in the Bitter Root Valley of Montana and 

 to some extent in the mountains of Idaho. It is an acute febrile affection with a 

 tendency to stupor. The eruption, which appears about the third to fifth day, is 

 not unlike that of typhus fever and tends to become haemorrhagic. Gangrene oi 

 penis or scrotum may appear. It is transmitted by a tick, Dermacentor andersoni 

 (D. venustus) which lives on domesticated animals of the region. Destruction of 

 ticks which attach themselves to sheep by dipping has been proposed as a measure 

 for eradication of the disease. Ricketts found that the reservoir for the virus is 

 to be found in ground squirrels, chipmunks, mountain rats, etc., and that ticks 

 feeding upon them become infected and so transfer the disease to man. Guinea- 

 pigs are susceptible as is also the monkey. Ricketts noted certain chromatin staining 

 bacteria in man and in eggs of infected ticks as possibly playing a part in etiology. 

 Quite recently Wolbach has reported the finding in infected guinea-pigs of organ- 

 isms, possibly bacterial, showing granular and lanceolate forms. They are par- 

 ticularly abundant in the endothelial cells of blood-vessels. They are from ^ to 

 i micron long by about J^ micron broad. Ricketts stated that his organisms were 

 about the size of B. influenza and showed as two lanceolate-shaped bodies. Wilson 

 and Chowning, in 1902, reported the finding of piroplasm-like organisms in the 

 blood of the disease. Ricketts proved that the virus was not filterable. 



Trachoma. This contagious form of granular conjunctivitis is 

 supposed to be due to chlamydozoa or inclusion bodies and is classed 

 as one of the filterable viruses. The relation of the trachoma bodies 

 to the Koch- Weeks bacillus is discussed under that organism. 



