Salvarsan. 



307 



cause. The average length of life in the eight observations sum- 

 marized above was five months. It has been assumed in some of 

 these experiments that the polyuria was permanent. I have made 

 observations which bear on the question of permanency. 



Dog 4; female, weight 6,135 gm., about 6 months old, had an 

 average daily output of 140 c.c. of urine. Jan. 5, 1920, under 

 ether anesthesia, the pituitary gland was exposed by Paulesco's 

 technic, and an incision was made through the tuber cinereum 

 which opened the third ventricle and completely separated the 

 stalk and gland from the base of the brain. The output of urine 

 rose for three days to about 600 c.c, dropped to 200 c.c. for the 

 following four days, and rose to 1,000 c.c. on the ninth day. From 

 that time until Apr. 1, the output was always above 1,000 c.c. 

 except when it was reduced for a day by injection of pituitary 

 extract. The largest amount was 1,450 c.c. on Feb. 26. From 

 Apr. 1 to May 22 the output varied between 800 and 500 c.c, 

 always tending downward. On June 5 it reached 250 c.c. and 

 remained there until June 24, when the animal was killed. The 

 polyuria had lasted about 20 of the 24 weeks after operation, and 

 during that period her weight rose to 1,250 gm. She was always 

 active and well, but did not come in heat. 



At autopsy there was a marked increase in adipose tissue. 

 The uterus and ovaries were infantile. The thyroid and adrenals 

 were microscopically normal. The ovaries showed ova in every 

 stage of development. A block from the floor of the third ven- 

 tricle, including the tuber cinereum and the attached pituitary 

 gland, was cut in serial sections. The scar of the operative in- 

 cision was at the lower margin of the optic chiasm anteriorly and 

 at a slightly lower level posteriorly. To this extent the floor of 

 the third ventricle had been reformed by connective tissue without 

 ependymal lining. All of that portion of the pars intermedia 

 which covers the tuber cinereum and the neighboring base of the 

 brain (limey's pars tuberalis) had been detached with the stalk. 

 The pars anterior appeared normal, with about the usual propor- 

 tion of chromophile and chromophobe cells. The pars nervosa 

 was atrophic and invaded by cells of the pars intermedia type. 

 Surrounding the altered pars nervosa was an empty space which, 

 from the evidence of a few sections, had been filled with colloid 



