Bovine obstetrics / by M.G. de Bruin ; translated by W.E.A. Wyman.

  • Bruin, M. G. de.
Date:
1901
Catalogue details

Licence: In copyright

Credit: Bovine obstetrics / by M.G. de Bruin ; translated by W.E.A. Wyman. Source: Wellcome Collection.

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    first respiratory movements are slow and deep, with decided movement of the abdominal muscles. A few moments later, slimy masses are expectorated and respiration becomes regu- lated, so that the respiratory movements become less deep and slow, but more frequent. Many physiologists have ventilated the question, What causes the first respiration ? Haller still thought that respira- tion depends on the various painful sensations, or probably desire for food. Buffon alludes to the stimulus exerted by air upon the olfactory nerves and upon the mechanism of respira- tion. Others believed that the influence of the cold air induces respiratory movements reflectorily. According to Kehrer, Blumenbach started the correct investigation of this question. He looks upon the cessation of the placental circulation as the primary cause of respiration, which explanation has been accepted by many. Kehrer thinks that experimental tokology should solve the question how far external irritations, as temperature of air and other natural processes occurring at parturition, are concerned in the production of the first respira- tion. For this purpose he experimented with newly born dogs still within the amniotic sac, by placing them into water of body temperature before the first respiration became mauifest. The puppies were quiet for one-fourth to three minutes and now and then opened and closed the mouth. After this time they began to squirm about and raised the head as if to catch air. Distinct respiratory thoracic movements were appreciated. Whenever the entrance of air was prevented, the animal attempted to breathe once or twice per minute, at the same time undergoing the above mentioned convulsive movements. Any pressure upon the body awoke the animal and instituted a strong respiration. After 14 minutes, respiration stopped and the heart ceased to beat after 36 minutes. Whenever the dogs were removed from the water, after lying in there for a few minutes, respiration began at once and the frequency of the heart-beats increased. From the above Kehrer makes this deduction : “The first respiration follows the interrupted placental circulation as a