78 BOVINE OBSTETRICS 



first respiratory movements are slow anil 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 influeDce 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 fiist 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 plaoental circulation :is a 



