364 
AURIGO VISENTINI. 
nuclear membrane. I believe that the appearances shown in 
figs. 28, 29 and 30 should be interpreted as early forms of 
multiplication. In these the nuclear chromatin is not 
collected, as in the majority of cases, in a compact mass 
forming a single kai’yosome at the centre, but is broken up 
into granules and short rods which perhaps correspond to 
chromosomes, and which, distributed at first ij-regularly in 
the sap-zone, afterwards arrange themselves so as to con- 
stitute a single elongated mass of irregular contour, disposed 
transversely to the longer axis of the organism and always 
contained within the nuclear membrane. Subsequently the 
chromatin collects at the extremities in two masses, which 
remain united by a thread that becomes continually more 
attenuated. Here also there is a true and proper centro- 
desmose with an achromatinic filament which stains strongly 
and resists prolonged differentiation with iron-alum ; it 
unites, as is seen specially in fig. 35, two stained granules, 
which correspond, I believe, to the centrioles of the daughter- 
nuclei. 
The nuclear membrane persists thi’oughout and can be seen 
well in the preparations stained with iron-hmmatoxylin, and 
better still in those stained by Giemsa’s method. In the 
latter it is seen that the membrane, like the whole nucleus, 
assumes at first an oval form, then is gradually constricted in 
half in the form of a figure of eight, disposed transversely to 
the greater axis of the Leishmania; when the two halves 
are joined by the delicate filament, it constitutes the mem- 
branes of the two rounded daughter-nuclei (figs. 11, 12, 13, 
14, 15, 16, 17, 18, 32, 33, 34, 35). Between the latter the 
centro-desmotic filament breaks and the division is complete. 
Meanwhile the division of the protoplasm has already begun 
(fig. 17), or follows rapidly. 
In spite of many long and patient observations I have 
never come across forms of division, either of the tropho- 
nucleus or the kinetonucleus, in which the presence was 
observed of an achromatinic spindle and of a typical 
equatorial plate, such as has been described in trypanosomes 
