1090 
contractions. He repeated Morrav’s second experiment, but took a 
fish whick bad ‘been narcotized with ether, and hence sank side- 
ways to the bottom of the glass basin. When the animal came to, 
it gradually raised itself without any motion of the fins and at the 
same time the meniscus in the capillary tube moved forward. 
GurÉror opposes this view of JAEGER, and tries to prove that both 
facts and interpretations in JAEGER’s study are incorrect. 
As it seemed to me that the investigations of both authors showed 
methodical defects, [ resolved to verify them. 
It was not difficult to confirm the general phenomena relating to 
fishes living under modified pressures, as described by Morrav, 
BAGLIONI, and others. I could establish that different fishes were 
sensible to a decreased pressure of from 1—2 centimeters of mercury. 
Already before this decrease became such as to drive upward a 
fish resting on the bottom of the basin, it showed by the restless 
motion of its fins that it responded to this decreased pressure. 
I found that in the experiments as carried out by Jancrr and 
GuyÉnNor, inaccuracies might slip in, which rendered the results 
absolutely unreliable, inaccuracies which seemed to have been noticed 
or taken into account by neither of these authors. 
The principal mistake was certainly the absence of any means 
of verifying temperature-changes in the water during the experiment. 
A large glass bottle into which a bent capillary-tube has been 
fastened hermetically must needs act as a water-thermometer. If the 
water in the bottle has not exactly the same temperature as the 
surroundings, considerable meniscus-movements will be the result, 
which are by no means due to the presence of the fish in the 
bottle. 
In the preliminary experiments, carried out without a fish, it 
became obvious that such meniscus-movements resulted indeed from 
temperature-changes. This rendered the results both of JAEGER and 
of Guyénor worthless as soon as the experiments of which they 
were the outcome were of a somewhat longer duration (e.g. a quarter 
of an hour or longer.) 
Hence it was necessary to find a means of eliminating the effect 
of the temperature. 
Therefore the bottle which served as a volumeter was placed in 
a large water-reservoir, from which the bottle itself was filled. ‘This, 
however, was found to be no decisive improvement. Changes in the 
temperature of the room where the experiments were carried out, 
always brought about a slight change in the temperature of the 
water. Therefore I placed a second bottle, identical with that used 
