PHYSIOLOGICAL PROPERTIES OF THE GONADS. 287 



1 6 x 1 6 x 30 inches, were fed daily with carrots and hay, and 

 usually all cages were supplied with grain (corn, oats) twice each 

 week. Each animal was weighed on each thirtieth day from 

 birth to the end of one year (360 days). As each weighing was 

 made by the writer, an absence of three weeks caused one weighing 

 of some animals to be omitted. 



To avoid differences due to the operation castration was accom- 

 plished by opening the peritoneal cavity of the young male by a 

 mid-ventral incision; the spermatic cord was tied off considerably 

 above the testis, and by cutting the cord below the ligature the 

 testis was removed intact. Spaying was accomplished by means 

 of two dorsolateral lumbar incisions (one on either side) tieing, 

 or clamping for a short time, the ovarian blood vessels, and re- 

 moval of the ovary with or without a considerable amount of the 

 oviduct. Post-mortem examination showed that in every case the 

 entire ovary had been removed. Each animal was castrated or 

 spayed before the thirtieth day and in the majority it was done 

 before the age of fifteen days. 



As the experiment approached its termination each animal was 

 killed with chloroform immediately after weighing (on the 36oth 

 day) and the following data recorded : total body weight (before 

 killing),, total body length, weight of the two thyroids, hypophysis 

 (pituitary body), the two adrenals, spleen, sex glands where pres- 

 ent, and the lengths of the femur, tibia, and fibula. 



In weighing the glands, except the hypophysis, all were rapidly 

 removed from the animal, cleaned of superfluous connective tissue, 

 and placed together in a ground-glass covered container, weights 

 being obtained by difference as each gland was removed to fixation 

 bottles. The weights were obtained as rapidly as possible, hence 

 the glands contained whatever blood or other fluids they possessed 

 at the moment of removal. 



In handling the pituitary, the cranial cavity was rapidly opened, 

 cranial nerves severed as the brain was lifted off the floor of the 

 cranial cavity, and the gland very carefully dissected from under 

 the membranes and immediately dropped into a weighing tube 

 containing the desired fixing fluids ; the weight of the container 

 and fluid had been determined immediately before the animal was 

 killed. In all cases the hypophysis was in the killing fluid and 



