448 proceedings: biological society 



THE BIOLOGICAL SOCIETY OF WASHINGTON 



The 542d meeting was held in the Assembly Hall of the Cosmos 

 Club, Saturday, May 15, 1915, with President Bartsch in the chair 

 and 43 persons present. 



On recommendation of the Council, Francis N. Balch, Boston, 

 Massachusetts, and Ernest P. Walker, Wrangell, Alaska, were 

 elected to active membership. 



Under heading exhibition of specimens, L. O. Howard showed lan- 

 tern slides from photographs of a moth, Ceratomia amyntor, bringing 

 out its protective coloration while at rest on bark. 



The first paper of the regular program was by C. H. T. Towtstsend, 

 Two years' investigation in Peru of verruga and its insect transmission. 



The four stages of verruga are defined as incubative, fever, quiescent 

 and eruptive. The most important symptom of the fever stage is the 

 presence of the bacilliform bodies (Bartonia bacilliformis Strong et al.) 

 in the erythrocytes. The histology of the eruptive papules is not yet 

 sufficiently defined for positive diagnosis in the absence of the clinical 

 history, but its chief feature is a marked proliferation of angioblasts. 



Verrugas Canyon is the best known and probably one of the strongest 

 endemic foci of the disease. Extended investigations were carried 

 on there both day and night at all seasons of the year. The result 

 was an ecological demonstration of Phlehotonms verrucarum Town- 

 send as the vector of the disease. This demonstration is built on the 

 unique etiological conditions already known. Verruga can be ac- 

 quired only by direct inoculation into the blood, is only contracted at 

 night, is confined to very restricted areas within which it is almost 

 universally contracted at any time of year by non-immunes who re- 

 main from 7 to 10 consecutive nights. These conditions necessitate 

 a blood-sucking vector which is abundant, active only at night but 

 throughout the year, and whose distribution is coterminous with the 

 infested areas. The above Phlehotomus is the only bloodsucker which 

 meets these requirements. 



Clinical verification of the vector was obtained from the history of 

 numerous cases of verruga observed by Dr. Townsend. Transmissional 

 demonstration in laboratory animals lacked completeness only by rea- 

 son of the impossibility of positively diagnosing verruga eruptive 

 tissue, papules having been produced in animals by injection of the 

 crushed Phlehotomus. 



A biting experiment was carried through, resulting in what appeared 

 to be a light infection. This was the case of McGuire, who exhibited 

 all the symptoms but with a paucity of the bacilliform bodies in the 

 erythrocytes. Papules appeared sparingly after the subject had been 

 discharged. Dr. Townsend's assistant, Mr. Nicholson, accidentally 

 received many Phlehotomus bites, thereby furnishing a clean experi- 

 ment with two checks. The checks were Dr. Townsend and his as- 

 sistant, Mr. Rust, both of whom were subjected to exactly the same 

 conditions as Mr. Nicholson except that they did not receive the 



