BIOLOGY. 
Prot. 39 
etc.) on Paramoecia. Movements of the animals soon cease, and agglutina¬ 
tion occurs, id. (208). 
Reactions of various Infusoria to carbonic and other acids; their 
“chemotaxis” or “ chemokinesis ” (collection in the drop introduced, or 
not), Jennings & Moore (170). 
(c) Electrical, thermotactic stimuli, etc.:—The reactions of 
various Infusoria to the induction-current (solitary induction-discharges) 
may be summarized as the expression of indirect excitation of the motile 
organs, especially of those belonging to the peristome region, which 
possesses a high irritability towards the electric stimulus, Roesle (318).— 
Galvanotaxis in Infusoria, studied on the positively galvanotactic (“anodic”) 
Opcdina ranarum , and on the negatively galvanotactic (“ kathodic ”) Colpi- 
divm colpoda and Paramcecium caudatum. If the “directive-cilia” work 
by means of the expanding-stroke, the Infusorian swims to the anode, if by 
the contracting-stroke, it is driven to the cathode. No different polarity 
in the anodic and cathodic forms need be assumed, for the same excitation 
that sends Paramcecium to the cathode, sends Opalina to the anode. Thus 
there are not two forms of galvanotaxis, since they are only apparent, 
owing to the different mode of action of the directive-cilia in different 
cases, Wallengren (409). 
Effect of Rontgen-rays on Paramcecium and Volvox. The vital functions 
suffer injury and (in Paramcecium) the contractile vacuole empties itself 
more slowly and less often. Paramcecium and Volvox are negatively tropic 
to the rays, Joseph & Prowazek (173). 
Thermotactic experiments on various Protozoa ; Mendelssohn (254- 
256) arrives at the conclusion that “ locomotile orientation in thermotaxis 
results from the action of a difference of intensity of the thermal irritant 
on the unicellular organism and is in relation with the vital energy of the 
locomotile organs.”—In Monas reduction of the temperature brings about 
the formation of many small spores, each of which, on again raising the 
temperature, gives rise to a motile individual ; variation in temperature 
controls method of reproduction, Greeley (147).—Lowering of the tem¬ 
perature brings about, in Stentor, certain definite morphological changes, 
and not simply a suspension of the vital activities ; these result in forma¬ 
tion of a spherical cyst and a resting stage ; hence the effect is similar to 
that caused by a loss of water, Greeley (146). 
Effect of pressure on the cytoplasmic structure in Paramcecium , Bursaria , 
Prorodon , Balantidium , Opalina and allied Ciliates ; action of indifferent 
salts, acids and alcohol, and other varied chemical and electrical treatment, 
Kolsch (178).—Effect of various stimuli on fixed Infusoria. The ani¬ 
mals were found to become accustomed to repeated mechanical stimuli. 
Whether they react to it or not, and how, depends upon previous subjection 
to this stimulus. If the stimulus continues, a not invariable series of 
reactions is given, each adapted by a different method to getting rid of the 
stimulus, Jennings (168).—Thigmotropic experiments on Euplotes ; effect 
of, on the protoplasm, Prowazek (302). 
In various Ciliates studied, the movements, and reactions to stimuli, of 
pieces of the organisms, are essentially similar to those of the entire 
animal. The different varieties of movement are, further, not due to any 
particular set of cilia, but to the peculiar (one-sided) method of striking 
which these all possess, Jennings & Jamieson (169).—The entire reflex 
action, from excitation to extrusion of the trichocysts, in Paramcecium 
termed “ holism ,” thus w T e get thermobilism , chemobolism , etc. from the 
exciting agent, Massart (249). 
Working of the myonemes and hydrostatic apparatus, in response to 
stimuli in Acanthometra and Acanthophracta , Schewiakoff (338). 
Experiments on the effect of darkness on Zoochlorellce symbiotic with 
Stentor and Difflugia , Averintzev (8). 
