1901] MICROSCOPICAL JOURNAL. 77 
the “rosace,”’ a rounded body bearing at its circumference 
little spherules, while the pigment was accumulated at 
the centre. This discovery of Laveran’s, at first regard- 
ed with the gravest suspicion by pathologists, was the 
first great step in the etiology of malaria. It supplied 
the means of distinguishing the disease from its counter- 
feits, and it explained the wonderful specific efficacy of 
quinine, till then given only empirically. Quinine is re-— 
markable in the circumstance that it acts with deadly ef- 
fect upon some microbes, in dilutions which are quite un- 
irritating to the human tissues. It can thus be given in 
sufficient doses to kill the malaria parasite in the blood 
without injuring the patient. Nine years after Laveran’s 
discovery, Golgi, of Pavia, who had been specially study- 
ing the “rosace’”’ form of the parasite, and who had. be- 
come convinced that the spherules at the circumference 
of the rosace were sporules of the microbe, announced 
that he had observed differences between the rosaces of 
tertain and quartian forms of fever, so great and so con- 
stant as to make him satisfied that they were two distinct 
species of organism. At the same time, he had made the 
extremely important observation that the. periods of oc- 
currence of the fever corresponded with the times of ma- 
turation of the rosaces. These all coming to maturity 
about the same time, shed their sporules into the blood, 
and this determined the febrile attack. The free sporules, 
then, according to his view, attached themselves severally | 
to other red discs constituting Laveran’s tiny ameba, and 
grew in the red corpuscles without causing symptoms till 
they had produced a fresh crop of sporules ripe for extru- 
sion; the time for this being two days in the tertian and 
three days in the quartian form. Thus the periodicity of - 
the intermittent fevers and their variety in that respect 
were alike explained. A few months later a third species 
of the parasite was recognized, having the peculiarity that 
some of its individuals, instead of being of rounded form 
