Parathyroids 



209 



amount of milk, which prevents tetany, the dogs kept normal on 

 any diet ; now when meat was given in excess, the dogs increased 

 in weight and were normal in all their actions. It was possible 

 by giving large amounts of calcium lactate by stomach tube to 

 restore the calcium content of the blood almost to the normal 

 level. From this condition it took a longer time than usual to 

 produce tetany on a milk free diet and when tetany occurred 

 serum calcium was always found lowered again. If tetany was 

 produced from the latent stage a single dose of calcium lactate 

 (5-10 grams) usually checked all the symptoms. Analysis of 

 serum calcium then always showed that at the moment, when the 

 symptoms were relieved, there was an increase in the calcium 

 content of the blood, showing that it is the actual absorption of 

 calcium which cures the symptoms. The same increase in serum 

 calcium was seen when milk checked the symptoms. Concerning 

 the relation between the blood calcium and phosphorus during 

 latent tetany and the clinical symptoms, the findings may be 

 summed up as follows : (a. ) Whenever the animals were brought 

 into tetany from a symptom free condition, the blood calcium 

 was always still further lowered; (b.) When the animals by 

 administration of calcium or milk were made normal again, the 

 blood calcium was always higher than during the symptoms of 

 insufficiency, (c. ) The level of blood calcium at which tetany 

 occurred seemed to vary and seemed to depend upon at what 

 level of blood calcium the tetany producing diet was started. 

 Inorganic phosphorus showed no regularity; it usually was higher 

 than normal. 



3. The protein metabolism in dogs with latent tetany on a 

 milk diet and without symptoms was normal. The non protein 

 nitrogen and blood urea were normal both in the latent state and 

 during tetany. 



4. Carbohydrate metabolism. The blood sugar was unchanged 

 in these dogs both during the latent stage and during tetany. 

 The tolerance for glucose given orally was lowered ; when calcium 

 in the blood was increased by calcium feeding, the tolerance was 

 distinctly increased. When the dogs were brought into tetany 

 by milk free diet the tolerance was lowered. The urine in one 

 experiment contained 10 per cent, of sugar during the test. The 

 blood sugar curves indicate that the lowered tolerance is not due 



