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J. Thomas Patterson. 



mates of other writers, and perhaps also for those cases reported 

 in the literature, where a freshly laid egg is said to contain an 

 embryo with a well-developed vascular system. The writer is con- 

 vinced that any appreciable extension beyond twenty-two hours is 

 not due to an increase in the length of time that it takes the egg 

 to traverse the reproductive passage, but rather to a rentention of 

 the egg in the lower part of the oviduct, on account of some influ- 

 ence inhibitory to laying. The writer has found, however, slight 

 variations in the length of time, but these are probably to be cor- 

 related with the variations in length of the oviduct in different 

 hens. 



When once it has been established that the time occupied by the 

 egg in its passage through the different parts of the oviduct is prac- 

 tically constant, we are then in a position to determine the rate of 

 development; because we need only to note the stage of develop- 

 ment in eggs taken from the different parts, and from the data thus 

 collected determine the time elapsing between any two stages. The 

 following table will give the reader an idea of these estimates, which 

 were determined from a study of hens laying daily (about one hour 

 later each day). The table also gives the exact time of each of the 

 stages described in the rest of the paper. 



