SEXUAL BEHAVIOR OF ALBINO RAT 133 



visual stimuli were thought to be effectual in arousing the pair- 

 ing impulse in the female bird. Andrews ('14) concludes that 

 visual stimuli are unessential in the conjugation of the crayfish. 

 Banta ('14) states that the wood frog is sexually excited at the 

 mating season by objects moving within the radius of several 

 feet. From this statement we infer that visual stimuli initiated 

 the excitement. No previous investigations of the sexual func- 

 tion of the visual receptors in the rat have come to the author's 

 attention. 



a. Operative technique. The eyes of rats were removed under 

 deep anaesthesia. A small piece of sterile cotton was immediately 

 inserted into the orbits to absorb blood accumulating from tran- 

 sected branches of the opthalmic arteries. After all bleeding 

 had ceased and the orbits were cleansed, the eyelids were brought 

 together and overlaid by a small cotton-celloidin dressing. Case 

 reports of the individual animals follow. 



b. Experimental results. Rat 26. Eyes removed at age of 

 thirty days. Tested at age of seventy days for copulation. 

 No signs of sexual excitement and no attempts at copulation. 

 Again tested at the age of seventy-seven days. Mounting and 

 palpation of female's sides frequent. Made complete copulatory 

 attempt once but apparently did not effect vaginal entrance. 

 Tested at age of eighty-two days. Copulation appeared for first 

 time. In a period of thirty minutes there were twenty-seven 

 complete acts. 



Rat 27. Eyes removed at age of thirty days. Tested for 

 copulation at age of seventy-six days. Showed hyperexcitability 

 but did not attempt to mount. Tested at seventy-seven days 

 of age. No copulation. At eighty-two days the test was again 

 given. Copulation appeared. Record for twenty minutes was 

 forty-nine complete acts. A remarkable exhibition of potency 

 was found in this animal. He copulated thirteen times during 

 the first three minutes, and the same number of times during the 

 second three minutes. 



In the foregoing experiments with animals, normal in every 

 way except that visual receptors were not present, no diminution 

 in sexual excitement was observed in the young males prior to 



