316 MAINE AGRICULTURAL EXPERIMENT STATION. I916. 



ent investigations. The data then on hand indicated that three 

 fundamental factors are concerned in dwarf egg production. 

 "These are : 



"1. The bird must be in an active laying condition; the more 

 pronounced the degree of physiological activity of the oviduct 

 the more likely are these eggs to be produced. 



"2. There must be some foreign body, however minute, to 

 serve as the stimulus which shall start the albumen glands 

 secreting. This foreign body may be either a minute piece of 

 hardened albumen, a bit of coagulated blood, a small piece ot 

 yolk which has escaped from a ruptured yolk, etc. 



"3. It seems likely, though this is a point not yet definitely 

 settled, that ovulation (i. e., the separation of a yolk from the 

 ovary) must precede the secretion of albumen around the 

 foreign body to form one of these eggs." 



To a large extent the complete investigation confirms and 

 extends these conclusions. The data which contribute to our 

 knowledge of the physiology of dwarf egg production are the 

 complete egg records and the autopsy records of dwarf egg 

 producers. 



A. EVIDENCE FROM THE EGG RECORDS AND AUTOPSY RECORDS OF 

 DWARF EGG PRODUCERS WITH ABNORMAL REPRODUCTIVE 

 ORGANS. 



It has already been noted that the egg records for eleven of 

 the 200 known dwarf egg producers showed that few or no 

 normal eggs were produced after the dwarf egg or eggs. Such 

 birds usually make nesting records, the dwarf egg occurring in 

 a series of the nesting records. As an illustration the egg 

 record of Case No. i is reproduced in Fig. 56. 



From this record it may be seen that the bird was a heavy 

 layer producing 162 eggs up to May 28. After this she pro- 

 duced only one normal egg (on June 26). The nesting records 

 occurring in clutches indicate that the ovary passed through 

 its normal cycles. Four dwarf eggs were produced in a series 

 of nesting records. 



Five of the eleven cases of dwarf egg producers cited above 

 were autopsied and found to have several things in common. 

 (1) Each bird was a normal high laying individual which 



