The Morphology of the Parasite

Soon after the occupation of the'Canal Zone by Americans, in I904, the medical officers of the Sanitary Department, on account of the numerous cases of splenomegaly met with among the Colombian natives, had their attention called by the work of Leishman3 and Donovan 4 to a very fatal endemic disease of India, known as kala-azar. The clinical features of this disorder being splenomegaly, emaciation, cachexia, irregular pyrexia, leukopenia and the presence of an intracellular protozoon in the endothelium of the liver,: spleen, lymph nodes, etc. Manson" in one of his prophetic utterances has stated that kalaazar or an analogous disease might be found in America, and before this, Ronald Ross, during his visit to Panalma in 1904, looked through the wards of Ancon Hospital in search of a case of splenomegaly associated with the kala-azar symptom-group, but none was found, although tropical splenomegaly is commonly seen in this region, particularly among the native Colombians; so common, indeed, that in the autopsy room it has been the custom to speak of examples of tropical splenomegaly met with here as "Colombian Spleens." The size of the Colombian spleen is due partly to an interstitial fibrosis and partly to lymphoid hyperplasia; etiologically,