368 MAINE AGRICULTURAL EXPERIMENT STATION. I912. 



TABLE 30 



Showing the results of mating class 2 B.P.R. <$ S with high laying 



Barred F^ ? ? 



Mating 



Observed Winter Production of Daughters 



B. P. R. c? 



Barred Fi $ 



Over 30 



Under 30 ' Zero 



552 

 554 

 563 

 564 

 567 

 562 



424 

 87 

 412 

 405 

 425 

 404 



3 

 



7 

 7 

 2 



5 

 4 

 1 

 2 

 1 

 4 















. 



3 









194 



iS 

 57.16 eggs 



134 

 IS 

 12.69 eggs 



3 



Total Expected 







Mean winter production 





visited a nest and laid, but also when she visited a nest and did 

 not lay. A large number of records have been accumulated of 

 birds which go through the whole process of nesting and laying 

 except that they do not discharge any eggs from, the body. It 

 was hoped to publish a paper on this subject, which throws 

 light on the problem of the physiology of egg production, before 

 the present paper appeared. This has not been possible owing 

 to pressure of other work, so it will be necessary to take a 

 little space here to discuss certain phases of this subject. It has 

 been shown- experimentally in the laboratory that if the oviduct 

 of a normal healthy hen, with a normal ovary, is ligated, tran- 

 sected or removed entirely, without injury to the ovary, such a 

 bird goes regularly through the entire process of laying, save for 

 the extrusion of an egg, which is physically impossible. The 'n' 

 (nesting) record of such a bird is precisely like a normal egg 

 record, showing the same phenomena of rhythm and cycles. 

 Each day's '11' in the record of such a bird represents an egg^'^ 

 which she would have laid, had she been physically capable oi 

 so doing. 



Birds in which the oviduct is occluded through some diseased 

 condition often behave in this manner. It may result from other 

 abnormal conditions also. With this explanation, the following 



"^ Oif course this does not mean that when a bird visits a nes.t twice in 

 the same day she would have laid two eggs that day had she been nor- 

 mal. Many laying birds have the habit of visiting the nest once or 

 twice in the same day before actually laying. 



