Blood Coagulation Time in the Dog. 97 



a constant temperature of 25 0 C. and the time recorded. After 

 each sample of blood had been secured the artery was thoroughly 

 washed out with Ringer's solution. 



When ten or more observations had been made, the wound, 

 after being cleansed with corrosive, was closed, and then both 

 lobes of the thyroid (including the parathyroids) were removed. 

 When the symptoms of tetany developed the animal was again 

 anaesthetized and the same procedure adopted on the right limb. 

 At the end of this last experiment it was killed by an overdose of 

 chloroform. 



In our later experiments we made three sets of observations 

 on each animal; in the first set the blood was taken from the left 

 saphenous artery, and a few days later, when this wound had 

 healed, the corresponding vessel on the right side was used. At 

 the end of this second experiment the thyroid (including the 

 parathyroids), was removed, and when symptoms developed a 

 third set of observations was made on blood withdrawn from the 

 right lateral circumflex artery, a branch of the femoral arising at a 

 higher level than the saphenous. The object of this procedure 

 was to find out whether, under normal conditions, the coagulation 

 time showed any variation from day to day in the same individual. 



Without going into detail, the results of our experiments, so 

 far as they have gone, seem to point to the conclusion that when 

 the symptoms of parathyroid tetany are pronounced (rapid breath- 

 ing, excessive tonic and clonic muscular contractions, etc.) the 

 coagulation time is prolonged, which may possibly indicate a low 

 calcium content for the blood. On the other hand, where the 

 symptoms are only slight (fine muscular tremors and no rise in 

 body temperature) or just beginning, the coagulation time either 

 remains unchanged or is somewhat shortened. 



The following are three examples taken from the thirteen ex- ' 

 periments which we have performed : 



Experiment I. Dog o". Weight 16.9 Kilos, Age 13 Months. 

 1st set of observations (average of 10 readings) — Coag. time 3 Yi min., normal. 



2d — " " 4^ " 



3d " — " " 6 " during tetany. 



In this case the symptoms, which appeared four days after 

 removal of the glands, were very severe: respiration 120, rectal 



