732 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
be discovered when a better survey has been made of freshwater lakes 
in other parts of the world. 
Pigment and Conjugation of Euglena.*— Sig. 0. Visart maintains 
that the red pigment (hsematochrome of Cohn) of Euglena sanguinea has 
a close genetic relation to chlorophyll, and is probably a derivative 
thereof. As the red pigment occurs most abundantly at the maximum 
of light and heat, it seems reasonable to conclude that the intensity of 
the sun’s rays is a factor in its formation. Sig. Yisart has also ob- 
served and figured the conjugation of two individuals of Euglena 
sanguinea , and their ultimate fusion into a spherical cyst. 
Monadine parasitic on Saprolegniese.f — Prof. M. M. Hartog gives 
an account of a monadine which he has observed in his culture of Sapro- 
legnieae. The mastigopod swarmer or zoospore stage may frequently be 
found in and about the infected hyphae of old cultures about nine o’clock 
in the evening or later. It is from 7 to 10 fx long ; each example has a 
nucleus of the rhizopod or myxomycete type — i. e. vesicular, with the 
nuclein in a spherical central mass, and there is at least one vacuole 
anterior to the nucleus. After a long period of active swimming, the 
parasites settle down on the walls of living hyphae, glide along them like 
Amoebse , and finally penetrate into them ; the pseudopodia are now 
radiate and stiffish. After using up the nutrient protoplasm, that of the 
parasites becomes coarsely granular ; the pseudopodia become retracted, 
and the granules are collected into a highly refractive excrementitious 
mass, surrounded by a clear vacuole and simulating a gigantic nucleus. 
These granules are obviously nitrogenous. The body of the parasite 
now becomes spherical. The nucleus gives rise to daughter-nuclei, and 
zoospores are, later, found. One bores through the cyst-wall, and the 
others follow through the same hole. The author calls this parasite 
Pseudospora (?) Lindstedtii , and, as its name implies, regards it as one of 
the Pseudosporacese. 
Parasites of Malaria. :J — Prof. B. Grassi and Prof. R. Feletti, who 
have been prosecuting investigations on the parasites of malaria, support 
the views of those who are in favour of considering the appearances to be 
due to the presence of a microbe. They are of opinion that the forms 
described by Laveran, Marchiafava, Celli, and others are really the 
parasites of malaria, and that in all probability they are amoebiform 
Rhizopoda, and that there are two genera, Hsemamoeba malarise, asso- 
ciated with the regular type of malaria, and Laverania malarise, found 
in connection with the irregular types of pyrexia. The observations of 
the authors confirm the actuality of the appearances insisted on by 
Laveran and others, and their views differ from those of their predeces- 
sors merely in their holding that the crescent-shaped bodies, called by 
them Laverania, and the amoeboid pigmented forms (Hasmamoeba) are 
representatives of two different genera, which when young are indistin- 
guishable. Both are possessed of a nucleus which behaves, in repro- 
duction, just as the nucleus of all other living beings does. Directly 
the plasmodium begins to grow the two genera show signs of difference, 
* Atti Soc. Tosc. Sci. Nat., vii. (1890) pp. 92-9 (4 figs.). 
f Ann. Bot., iv. (1890) pp. 337-46 (17 figs.). 
% Centralbl. f. Bakteriol. u. Parasitenk., vii. (1890) pp. 39G-401, 430-5. 
