THE GENERA HERPETOMONAS AND CRITHIDIA 239 



however, R. Ross, examining the I^eishman-Donovan bodies, came 

 to the conclusion (November 14, 1903) that they were distinct forms 

 of protozoa, and named the organism causing kala azar Leishmrmia 

 donovani, but Rogers ('05), on the basis of culture experiments, found 

 no perceptible difference between the flagellated phase and herpeto- 

 monas, while Patton ('OS) has demonstrated that the non-flagellated 

 phases are likewise identical. The genus leishmania, therefore, 

 cannot hold. If the organisms discovered by Wright are found to 

 belong to the same genus, but are specifically different, then the name 

 for Wright's organism must be Herpetomonas tropica, Wr. 



Rogers' discovery of the flagellated stage was quickly confirmed 

 by Christophers and by Leishman, the latter finding in this dis- 

 covery a confirmation of his earlier belief that the organisms were 

 trypanosomes, basing his view on the fact that some trypanosomes 

 under culture have no undulating membrane. Rogers gave many 

 reasons for considering the bedbug the means of transmitting the 

 disease from individual to individual, and his surmise was not only 

 confirmed, but the transformation of the intracellular bodies into 

 flagellates within the intestine of Cimex rotundatus was fully worked 

 out by Patton in 1907. With this discovery Leishman's conclusions 

 regarding the trj'panosome relation cannot hold, the organism finding 

 its nearest relative, as stated above, in the genus herpetomonas. 



The Leishpian-Donovan bodies, as the intracellular forms have been 

 called, are present in large numbers in the cells of liver, spleen, and 

 bone marrow, while, according to Christophers, leukocytes and great 

 macrophages of endothelial origin may become crowded with them, 

 100 to 200 in a single cell (Leishman). They are taken into the 

 stomach of the bedbug still as intracellular forms, and are liberated 

 there by degeneration and digestion of the human cells. When first 

 liberated, and during the early changes in the gut, the parasites 

 measure from 4 to 7 /^ (Patton); they may be oval or spherical in 

 shape, but they soon divide and may form small "rosettes" of six to 

 eight cells. 



No sexual differences and no conjugation processes have been made 

 out, although Leishman described the formation of verv slender forms 

 from larger ones (Fig. 94) in organisms under culture; such conjuga- 

 tion processes are to be sought in tiie intestine of tlie l)e(lbug, and it 

 may be predicted that within a very short time they will be found there. 



Herpetomonas donovani, in its quiescent phase, is undoubtedly an 

 endothelial cell parasite which multiplies in human tissue cells until 

 the normal histological relations of such cells are broken down and 

 the cells are liberated as macrophages in the general circulation. Here 

 many of the parasites l)ecome free, only to be caj)tured and ingested 

 by leukocytes, so that toward the end of the disease the perij)heral 

 blood contains great mimbers of parasite-filled leukocytes and endo- 



