648 TRANSACTIONS OF SECTION T. 
fields. The movement is identical with that obtained with short inorganic 
filaments, and is a consequence of the relative electrical conductivity or 
specific inductive capacity of the body and the surrounding liquid. 
To obtain the diatoms a pond scum was used, rich in animal and 
vegetable organisms. On trying the effect of direct currents the movement 
was remarkable. Elongated organisms orientated as before into line with 
the current, but at the same time there were two movements of translation, 
several animal cells moving against the current—i.e., towards the positive 
pole—and vegetable cells towards the negative pole. The movement started 
and stopped instantaneously with the current, and had all the appearance 
of a forced mechanical action similar to that obtained with inorganic 
matter. The sliding action of the two kinds across one another in opposite 
directions was very striking. Separate examination of the organisms gave 
the same difference, but motility of any kind led to cross effects. 
On repeating the experiment recently (June-July 1909) the same results 
were obtained. Blood cells of any animal and the contents of infusoria were 
found to move towards the positive pole. The contents of small fresh-water 
worms moved within the skin in the same direction, clearing the sac at one 
end or side. Those which moved towards the negative pole were the cells of 
algee and bacteria. Filaments of vaucheria anchored at one end and at right 
angles to the poles moved towards the negative. Out of several hundred 
observations not more than ten were of doubtful sign. As an example, a uni- 
cellular alga was found to move on the glass slide equally well in either 
direction, the two movements being simultaneous. It was suspected that 
the cleaning of the slide by rubbing with a cloth electrified its surface, 
so that when the cells were transferred to it they received other electrifica- 
tion. Passing the slide through a bunsen flame before use removed the 
surface charge, and the movement was then always to the negative. Para- 
mecium has*been found to move to the negative pole, but ciliates of any 
kind have both the stimulus to movement of the cilia and that of the cell 
contents in the above manner. I find that paramzcium always bursts 
towards the positive pole under the influence of the electric field. All the 
observed actions reverse when the direction of the current is reversed, and 
care must be taken to eliminate the effect of streaming under the cover slip. 
The effects are so well marked that ong is led to hazard the speculation 
whether the essential difference between animal and vegetable matter is that 
animal cells are on the whole negatively electrified (and so move to the 
positive pole), and vegetable cells positively electrified. The difference may 
extend to the protoplasm. 
In support of this there is the fact that the electrical response current 
in an animal skin is opposite in sign to that in a vegetable skin; one is 
ingoing, the other outgoing, suggesting an essential difference between the 
internal electrical states. 
It is difficult to find an explanation of the difference in the movement 
which does not introduce difference in the electrical charge of the cells. 
There is no change of the shape or dimensions. 
In order to observe the effect with certainty it is necessary to use non- 
motile cells and an electrical pressure of about 50 volts per centimetre 
through a thin film of liquid. 
8. Causal Factors in the Diurnal Variation in Body Temperature. 
By SurHeruanpD Stmeson, M.D., D.Sc. 
The temperature of the human body is not constant, but shows a well- 
marked diurnal variation. The minimum is reached in the early morning 
some time between two and seven o’clock, and the maximum in the after- 
noon between four and eight o’clock. The cause of this normal fluctuation 
