380 
L)K. AlilUGO VISENTINI. 
Even after thirty minutes up to an hour the first stages of 
the phagocytosis are still to be observed ; mononuclears 
which contain forms greatly altered show others in process of 
being engulfed, while other flagellates still quite intact 
l•emain free and perfectly mobile in tlie serum, like tliat 
shown in Fig. 7, twenty-five minutes after the injection. 
I have also made, as already stated, preparations of the 
peritoneal exudation of the animals sacrificed at various 
periods up to ninety-three days after the injection of the 
cultures and I have never seen Leishmanias or remains of 
them in the mononuclears, although I have dii'ected special 
attention to this point, because Laverau and Mesnil have 
observed the peritoneal infection up to fifty-nine days after 
the injection of emulsioii of organs of a dog infected with 
experimental leishmaniosis and have obtained subcultures of 
this fluid. 
Contemporaneously with the examination of the peritoneal 
fluid I have repeatedly made an examination of the peri- 
pheral blood, and, in animals sacnficed, I have made smears 
of the various organs ; in spite of the most patient investiga- 
tion 1 have never met with any form of Leishmania or any 
flagellate parasite in my numerous preparations. 
The facts described permit me to assert that we are deal- 
ing with a process of phagocytosis pure and simple ; it can- 
not be admitted that the flagellate leptomonad forms are 
transformed into Leishmania-forms and as such continue to 
live in the mononuclears, ])roducing a slight infection 
localised in the peritoneum, of the type of that obtained by 
Laveran and Pettit, because we are witnesses here of a 
gradual alteration and destruction of the parasites by a 
pi’ocess which leads t(j the final disruption of all remains of 
the injected Protozoa. It is scarcely necessary to add that 
in ihe forms engulfed every sign is lacking of a process of 
multiplication. Moreover the results of attempts to make 
cultures confirm fully this interpretation, and give a proof 
of it which I think can be regarded as absolute. In every 
animal killed with chloroform I have made cultures in blood- 
