C. kK. Watanabe 258 
this action may be observed only after entire parathyroidectomy and not 
when the removal of the thyroid leaves the parathyroids intact. Underhill 
and Blatherwick (20) also demonstrated that this hypoglycemia can be 
restored to normal temporarily and the tetany abolished for a time by the 
injection of calcium lactate. 
From the work of Paton and Findlay (1) it appears that the 
symptoms of idiopathic tetany are identical with those of tetania 
parathyreopriva and that in both conditions there is an increased 
excretion of guanidine base (13) which is a well known convulsant 
toxin. The injection of such drugs induced the almost identical 
symptoms of tetania parathyreopriva (7). Therefore, it is pos- 
sible that the chief cause of tetany is the production of relatively 
enormous quantities of guanidine bases in the body as a result 
of the impairment of the parathyroid function. Furthermore, if 
these guanidine bases are the sole source of the symptoms of 
tetany it seems interesting to inquire whether there is any cor- 
relation between the hypoglycemia produced by the parathyroid- 
ectomy and the guanidine content of the blood. 
The present investigation deals with the influence of the injec- 
tion of guanidine bases upon carbohydrate metabolism, especially 
the sugar content in the blood. 
Methods. 
Rabbits were used in this investigation. Blood was usually drawn 
from the ear vein before and after the subcutaneous injection of a 10 per 
cent solution of guanidine hydrochloride. McDanell’s (21) modification 
of the Lewis-Benedict method was used for the estimation of sugar in the 
blood and Fehling’s test for sugar in the urine. Duplicate determina- 
tions were done on the blood sugar to avoid technical errors. It was neces- 
sary to take some blood samples at night. In this case the specimen was 
immediately evaporated to dryness with the picric acid and determined 
colorimetrically the following morning. , All specimens were evaporated 
to dryness with picric acid immediately on being drawn in order to avoid 
disappearance of sugar. 
For the determination of total solids, the blood was drawn from the ear 
vein into a weighed crucible and dried to constant weight in an electric 
oven. About 2 cc. of blood were used for this determination and the 
sample for the blood sugar determination was taken at the same time. 
Comparison was made between normal rabbits and rabbits which had 
been injected with guanidine. 
To determine the sublethal dose of guanidine hydrochloride 
