270 THE PROTOZOA 



same species, it would appear that such variations cannot be utilized 

 as a means of separating the three species. 



With animal inoculations we formerly thought that the parasite of kala-azar 

 could be differentiated from that of infantile leishmaniasis by the fact that dogs 

 could not be infected with L. donovani, while they were susceptible to infections 

 with L. infantum. Recently Donovan and Patton have successfully inoculated dogs 

 with kala-azar splenic material. Patton found the parasites in the liver, spleen and 

 lymphatic glands as well as bone marrow of the inoculated dogs. Consequently we 

 cannot separate the two visceral leishmaniases from a standpoint of susceptibility 

 of the dog. Monkeys are susceptible to both diseases. 



As regards separating oriental sore from the visceral leishmaniases Gonder has 

 shown that white mice may be infected with both kala-azar and oriental sore, there 

 being produced in each case a general infection with the presence of parasites in 

 spleen and liver. A point of difference, however, is that the oriental sore mice 

 develop lesions on feet, tail and head which was not observed with the kala-azar 

 mice. There are some reasons for thinking that in human cutaneous leishmaniasis 

 a generalized infection may precede the local manifestations. 



A very interesting point is that the dogs in India never show a 

 natural infection with L. donovani while in the regions where L. in- 

 fantum is responsible for human infections the natural infection of 

 dogs is not uncommon, indeed many think the dog the reservoir of 

 virus for both L. infantum and L. tropica. It has been suggested that 

 the dogs of India, where kala-azar prevails, may be immune. 



As regards morphology it is usually stated that the parasites of the three species of 

 Leishmania are practically identical. In cultures it has been noted that the flagella 

 of L. tropica are longer and more twisted than those of L. infantum. Again it has 

 been observed that the parasites of the Oriental and South American skin lesions may 

 at times show a flattened or band-like trophonucleus instead of the constant round 

 or oval one of the visceral leishmaniases. 



Escomel has reported the finding of flagellated Leishmania in the South American 

 sores. 



Laboratory Diagnosis. The leukemias can be easily differentiated 

 by the blood picture, an important matter because the spleen of 

 splenomyelogenous leukemia is very friable and the danger from splenic 

 puncture is far greater in this condition than in kala-azar. Banti's 

 disease with its leucopenia shows a rather similar blood picture and 

 can only be surely differentiated by the finding of leishman bodies in 

 kala-azar. 



Malta fever, typhoid and the paratyphoids are best differentiated by blood cul- 

 tures or agglutination tests. 



Until recently it was recommended that for diagnosis our best procedure was 



