TRANSACTIONS OF THE SECTIONS. 119 
in the arm and wrist. <A fracture in a bone could, in fact, be easily made out, or 
growth from bone in these parts. In a very thin young subject, the movements 
and outline of the heart could also be faintly seen in the chest; but the light he 
had as yet employed had not been sufficiently powerful to render this demonstration 
all he could desire. It would be possible, lastly, to see through some diseased 
structure, so as to ascertain whether, within a cavity, there was a fluid or a solid 
body. The author concluded by stating that his object had been rather to mark 
the origin of a new and progressive step than to explain a perfect instrument, or 
record an extended series of successful results. 
On Effects of Extreme Cold on Organic Function. 
By Dr. Ricnarpson, F.R.S. 
The author passed in brief review his experiments performed at Dundee in 
relation to the effects of feezing the centres of the nervous system. He showed 
that in the lower classes of animals, such as frogs, the nervous centres can be 
frozen for long periods of time, with recovery after entire unconsciousness and 
apparent death. The points added on this occasion were in continuation of this 
line of research. The author first dwelt on the question whether frozen animals 
(such as frogs) respire during insensibility, and explained that they did not. In 
proof of this he said that animals so treated could be oe without harm in gases 
which would not support life, such as nitrogen and hydrogen, and could, be re- 
covered at the precise moment of solution from the frozen state when respiration 
was recommencing. He had placed animals in this way in hydrogen, nitrogen, 
and carbonic acid. In other experiments, when the animal was frozen, it was 
immersed in ether, and allowed to lie under the fluid until, by the rising of bubbles 
of air, indications of returning life were gained: then, taken out, the animal would 
recover. The gradual return of heat was thus a pure restorative, and the facts 
helped to explain many accounts as to restoration after freezing, which up to this 
time had been stated as strongly on one side as they were doubted on the other. 
The second point considered had relation to the effects on the circulation of freez- 
ing the brain. The author here showed that in warm-blooded animals the effect 
of reducing the temperature of the brain was to produce a gradual slowness of the 
circulation, and, when the freezing was carried to the lower part or base of the 
brain, to produce the condition of heart and pulse known as intermittency, fol- 
lowed, if the operation were continued, by the entire cessation of the heart’s 
moyement. This was a point of great practical moment as indicating the influence 
of the brain on the heart. Whenever the brain was reduced in physical power, as 
from intense mental fatigue, or shock, or anxiety, irregular action (intermittency of 
- the heart) was almost the necessary result. Most people were conscious of this, and 
often thought with great alarm that they were suffering from disease of the heart, 
when in fact they were merely labouring under temporary exhaustion of the brain. 
The third point went to show that under the influence of extreme cold on the 
nervous centres (the brain and spinal cord) the extreme effect of such active poi- 
sons as strychnine could for a time be entirely suspended. This raised a hope that 
in such diseases as tetanus, a new and successful mode of treatment might be gra- 
dually evolved. The fourth point had relation to the influence of extreme cold in 
preventing and even in removing the rigidity of death. Because the body after 
death cools, the inference had been drawn that the rigidity of death was due to the 
process of cooling. This was the exact reverse of the fact. The rigidity of death 
was quickened by heat, and prevented by cold, probably for an illimitable period 
of time, the cold being sustained. Further, by taking an animal already rigid, 
freezing it, and thawing, the first rigidity could be removed and the body become 
flaccid. The last point touched upon related to the effect of freezing and rapidly 
thawing the skin of certain regions of the body. It was shown that birds treated 
in this manner presented the extremest irregularity of movement, and other signs 
of nervous disturbance. Thus by freezing and rapidly thawing the skin on the 
side of the neck of a pigeon, the bird for a time walked sideways in the opposite 
direction, The author designated this effect as peripheral nervous shock. 
