756 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
quotidian ; H. vivax , cause of tertian ; and H. malarise, cause of quartan 
ague. The Laverania are said to be the cause of fever of irregular type. 
After much discussion the malaria-parasites are finally assigned to 
the Amoebae. It is to be hoped that when the final publication appears 
it will be illustrated so that an approximate idea may be obtained of the 
parasites in their different stages and varieties. 
Researches on Low Organisms.* — M. J. Massart has investigated 
the sensibility of marine unicellular organisms to concentration. He 
finds that organisms which have become accustomed to live in a medium 
of constant concentration generally avoid solutions which are more or 
less strongly concentrated. These results are in accordance with those 
obtained by the author with the human conjunctiva, for he finds that it 
is sensitive to more or less strongly concentrated tears. 
With regard to the effects of gravity, M. Massart finds that not only 
Flagellata, but also Bacteria and Ciliata are mobile organisms that are 
sensitive to weight. Two closely allied species of Spirillum gave totally 
different geotaxic reactions ; the geotaxy of Chromulina Woroniniana 
changes its sign according to the temperature. Contrary to the opinion 
of Yerworn, the author thinks that the accumulation of unicellular 
organisms in the superficial strata of liquids is due to irritability. 
Zoochlorellae.|— Dr. W. Schewiakofif remarks that Prof. A. Famin- 
tzin,J in discussing the zoochlorellae found in Infusorians, has ignored 
the observations which he (Schewiakofif) made in 1887, showing that the 
isolated Zoochlorella conductrix of Frontonia leucas could survive and 
multiply, and could be introduced into colourless varieties of Frontonia. 
* Bull. Acad. Roy. de Belgique, lxi. (1891) pp. 148-67. 
f Biolog. Centralbl., xi. (1891) pp. 475-6. 
X Mem. Acad. Imp. Sci. St. Petersb., xxxviii. 
