Bauhaus-Universität Weimar

Titel:
Handbook for the Physiological Laboratory. Text
Person:
Burdon-Sanderson, John Scott E. Klein Michael Foster T. Lauder Brunton
PURL:
https://digitalesammlungen.uni-weimar.de/viewer/image/lit18583/426/
BY DB. MICHAEL FOSTER. 
417 
withdrawal. It will be found to be greatly prolonged. In other 
words, irritation of the optic lobes has interfered with, or par¬ 
tially inhibited, the reflex action of the cord. If the optic lobes 
be removed, and the medulla irritated instead, the result will be 
much less marked. 
Obs. V. Having prepared a frog with optic lobes, and de¬ 
termined the reflex interval as above, inject into the back J grain 
of quinine sulphate and determine the interval again from time to 
time. It will be found to be much prolonged. 
Having prepared a frog with divided medulla (Chapter 
XXXIII.), and determined the duration of the reflex interval, 
inject the same quantity of quinine, and again determine the in¬ 
terval as before. No prolongation of the interval will be observed. 
These results may be explained by supposing that the quinine is 
unable to act directly on the reflex activity of the cord, but is 
able either to stimulate an inhibitory mechanism in the brain, or 
at least to affect the brain in such a manner as to interfere with 
the reflex actions of the chord. 
Obs. VI. Removal of the Cerebral Hemispheres in the Bird.— 
Select a vigorous pigeon, so young as to be just able to fly well. 
Keep it on dry food for a few days, in order to avoid an excess of 
bleeding. 
Having placed it under chloroform, using as little chloroform 
as possible, make an incision in the median line over the roof of 
the skull, and hook back the two flaps of skin. The thin skull 
may now be easily cut through with a pair of scissors, and the 
roof removed. Without waiting to stop the bleeding, draw the 
cerebral hemispheres gently forward, and carry a traverse incision 
from side to side with a blunt-pointed bistoury through the brain 
in front of the corpora bigemina, and with a narrow spatula 
remove the hemispheres en masse from behind forwards. Place 
the animal on a perch, and leave it to itself. Do not attempt to 
q plug or staunch the bleeding; a clot will soon form and serve as 
4 the best protection against further bleeding. Postpone putting 
râ sutures into the flaps of skin until the bleeding has wholly ceased. 
If it be desired to keep the animal alive for any length of time, 
it will be as well to allow it to remain perfectly quiet for some time 
after the operation, avoiding all observations and experiments upon 
Prit. Only on the second or third day begin to feed it gradually with 
s a fewr grains of softened barley or of rice. 
Otherwise, observations may be begun as soon as the bleeding 
îrfhas ceased. 
The bird so deprived of its cerebral hemispheres (together 
rwwith its corpora striata and optic thalami) if placed on the Anger 
rioor on a perch, will settle itself in a balanced position, and remain 
dithus for an indefinite period motionless, or all but motionless, 
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