NEW OBSERVATIONS ON OVARIAN GRAFTING. 9 



ovary of a second young" black guinea-pig-, of like age with the first but of 

 different ancestry. After the albino had fully recovered from the second 

 operation, she was placed with an albino male, No. 654 (fig. 3, pi. l) with 

 which she remained until her death about a year later. 



On the 23d of July, 198 days after the first operation, she gave birth to 

 two female young-. One was black but bore a few red hairs. A photograph 

 of this animal (No. 1970) at the age of three or four months is shown in 

 fig. 6, pi. 2. The other young one (No. 1969) was likewise black, but had 

 some red upon it, and its right forefoot was white. (See fig. 5, pi. 2.) 



On October 15 the grafted albino bore a third black young one, a male 

 which, like those previously born, had a few red hairs interspersed with the 

 black. A photograph of this animal is shown in fig. 4, pi. 2. 



On January 11, 1910, the grafted albino was observed to be pregnant for 

 the third time, and this time she was very large. Unfortunately, on Feb- 

 ruary 2, she died of pneumonia with three full-grown male young in utero. 

 The skins of these animals were saved and a photograph of them is shown 

 in figs. 7-9, pi. 2. Like the other three young they were black, but with 

 a few red hairs among the black ones. They bore no white hairs. 



An autopsy made one hour after the death of the mother showed on the 

 left side a distinct ovarian mass about a centimeter from the coiled part of 

 the oviduct; that is, approximately in the position where the graft from the 

 pure black guinea-pig was fastened at the first operation. On the right 

 side the mesentery of the oviduct was adherent to the body-wall where 

 an incision had been made at the second operation, and a small amount of 

 tissue, regarded as possibly ovarian, was there observed. Both this and 

 the ovarian tissue from the left side were preserved in Gilson's fluid for 

 sectioning and microscopic examination. The tissue from the left side was 

 found to contain numerous large egg-follicles, some already well advanced 

 containing a lymph space; in addition a number of corpora lutea were 

 observed. On the right side was found a small amount of undoubted ova- 

 rian tissue, with one well -advanced egg-follicle, but the whole apparently 

 was strongly encapsulated, so that no eggs could be discharged even if they 

 came to maturity. 



It is interesting to note that both grafts persisted, though taken from 

 different animals and transferred at different times. This result suggests 

 a possible susceptibility on the part of the animal grafted. 



Female 1970 (fig. 6, pi. 2) daughter of the grafted albino, was mated 

 with the albino male, her father (fig. 3, pi. l), and bore three young, two 

 of which were albinos and one black with some red hairs. If female 1970 

 had been the daughter of a pure-black mother, instead of a grafted albino, 

 we should have expected her to produce an equality of black and of albino 

 young. The observed result was the nearest possible numerical agree- 

 ment with this expectation. 



A control mating of the albino male, 654, was made with a female of 

 pure black stock. As a result there were produced two litters of young, 



