Abstract
Thirty-eight rabbits were exposed to anoxia for short periods during which the oxygen percentage in the mixture with nitrogen was so slowly decreased as to avoid excitement, though in some instances the anoxia was prolonged until respiration ceased. This slow deprivation of oxygen is termed anoxic shock. The rabbits were exposed to from 1 to 51 anoxic shocks during a period of from 1 to 60 days. The duration of a single shock varied from 15 to 60 minutes. Twenty-nine other rabbits were injected with insulin sufficient to produce coma and convulsions.
The symptoms of the insulin and anoxic shock were similar except that those due to anoxia occurred on a more rapid time scale. Anoxia was characterized by increase of the respiratory rate, dilatation of the ear arteries, muscular weakness, somnolence and finally decrease of the respiratory rate and complete cessation of respiration, though the heart continued beating. In insulin shock muscular weakness and somnolence also occurred before convulsions and coma. Here, too, respiratory arrest was observed. With anoxia 2 types of convulsions might be distinguished. A too rapid diminution of the oxygen percentage precipitated convulsions. A more interesting type of convulsion was observed following the resaturation of the blood with oxygen. Characteristically these convulsions could be suppressed by lowering the oxygen percentage again.
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