THE BROODING INSTINCT IN THE DOMESTIC FOWL 281 



days after this egg was laid, without any intervening production 

 whatever, the bird became broody again on June 14. 



The above described observations on normal hens, indicating 

 that the brooding instinct may become manifest without rela- 

 tion to antecedent laying, is supported by experimental work 

 carried on in this laboratory. Such evidence is derived from cases 

 in which the oviduct was completely removed from the bird by 

 a surgical operation, making it impossible for that bird to lay 

 thereafter. Two cases of this sort will be cited here. The pro- 

 tocols of the operations will be given first and then an account 

 of the subsequent behavior of the hens. 



Operation No. 34. November 13, 1908. Bird No. 91 1C. 

 Hatched June 11, 1908. Body weight, 1,480 grams. Under 

 ether anaesthesia 2 the oviduct was completely removed, with the 



Figure 11. Showing the record of bird No. 320. 



exception of that part of the vagina which is closely attached to 

 the cloacal wall. The left ureter was tied off and cut with the 

 oviduct. All of the ureter, however, was left in the body. The 

 oviduct at the time of the operation was in infantile condition. 

 This bird made an uneventful recovery from the operation. 

 She died and came to autopsy June 14, 1909, that is, 213 days 

 after the operation. The autopsy record is as follows: The ovi- 

 duct was found to have been completely removed, with the ex- 

 ception of the vagina, which was closely attached to the cloaca. 

 Left ureter had been cut and ligated. It was very much 

 enlarged and filled with a white mass of urates, etc. Evidently 

 the left kidney had almost entirely atrophied. The portion 

 still remaining was covered with a heavy layer of fat. The 

 right kidney had hypertrophied. Remainder of viscera normal. 



Administered according to the method described by Pearl and Surface (8). 



