C. Basile 
367 
In the parasite we can distinguish two masses of chromatin, the larger is 
called the nucleus, or trophonucleus, the smaller is called the blepharoplast, 
or kinetonucleus. Novy has also described a small well defined organ, the 
rhizoblast. The plasma appears finely granulated and in the large forms shows 
vacuoles. 
The nucleus is rounded and often appears as a compact mass (Plate XXI, 
fig. 1); occasionally it seems to consist of small grains of chromatin; at times 
it shows a minute body more deeply coloured, placed centrally or eccentric¬ 
ally, which recalls the karyosome (in sensu lato); very rarely the nucleus is 
absent. 
The blepharoplast is rod-shaped (Plate XXI, fig. 1) or pointed (Plate XXI, 
fig. 2), almost always detached from, but at times attached to the nucleus 
(Plate XXI, fig. 2). Visentini, who has carefully studied the morphology of 
Leishmania in the vertebrate host, thinks that this attachment of the ble¬ 
pharoplast to the nucleus indicates the nuclear origin of the blepharoplast; 
sometimes the blepharoplast may be absent (Plate XXI, figs. 4, 5). 
In parasites derived from haematopoietic organs, the rhizoblast occurs as 
a minute body or rod placed between the kinetonucleus and the peripheral 
zone of the parasite. In canine leishmaniasis, smears from such organs reveal 
the presence of granular forms which I believe to be connected with Leish¬ 
mania , but I cannot say definitely whether they represent a phase of the de¬ 
velopmental cycle and are comparable with the granular forms of trypano¬ 
somes, or whether they represent degenerative forms of the parasite. 
Reproduction. According to all authorities, Leishmania reproduces itself 
by simple longitudinal division; division of the nucleus and of the blepharo¬ 
plast is first observed (Plate XXI, figs. 5, 6); then the plasma divides. This 
form of agamic reproduction leads to the formation of characteristic bodies 
consisting of several parasites enclosed in a common protoplasm; Ross sus¬ 
pected a sporulation phase; Nicolle on the other hand, considered them to be 
parasites enclosed in the plasma of the leucocytes whose nucleus might have 
become detached in the process of preparing the smear. 
Besides the reproduction by simple longitudinal division, from which two 
individuals morphologically indistinguishable are produced (equal division), 
I have found that sometimes the longitudinal division gives origin to two 
individuals which can be morphologically distinguished (unequal division); 
I call the equal division “ homomorphous ” and the unequal division ‘hetero- 
morphous.” 
In heteromorphous division the blepharoplast takes no part whatever in 
the process of division, which occurs only in the nucleus (Plate XXI, fig. 7). 
Visentini described, without giving any explanation, the existence of para¬ 
sites consisting of plasma enclosing a nucleus but no blepharoplast (Plate XXI, 
fig. 4). I have decided that such forms result from an unequal division wherein 
no division of the blepharoplast occurs, the nucleus dividing into two equal 
similar nuclei, the plasma also dividing immediately. Two parasites are thus 
