O. Riddle and J. A. Harris 169 



I iummarizing these statements on correlation we note: At the 

 ei of the first laying year, in October, the correlation between 

 t\ per cent of fat in the blood and the annual egg record of the 

 y&amp;lt;r is positive in the case of birds which are still laying, but 

 mative in the case of birds which have ceased laying; or, in 

 oler words, birds which have laid larger numbers of eggs and are 

 stl laying have a higher percentage of fat in their blood than lay- 

 ir birds which have made a poor record during the year. Birds 

 w.ch have laid a large number of eggs, but have exhausted their 

 feility, have a smaller per cent of fat in their blood than non- 

 laing birds which have made poor egg records. 



3y dividing records into classes, according to the number of 

 cbs since the cessation of laying, the correlation between October 

 hod fat content and annual egg record changes systematically 

 fr n a positive to a negative relationship. 



This brief discussion will perhaps indicate how useless it is to 

 d w conclusions concerning correlations between blood fat and 

 anual egg production without actually determining the cor- 

 ration coefficients. The constants given here are of course 

 Sbject to the limitations of the series of data upon which they are 

 bsed. Larger sets of determinations, made at various times of 

 tl year, when analyzed by proper statistical formulas, should 

 yd further important information on the relation of fat metab- 

 oim to the functioning of the ovary. 



Addendum. In the foregoing treatment of the data published by Warner 

 ail Edmond 1 we had two purposes: (a) to call the attention of biological 

 cl mists to earlier work on the same subject which those authors entirely 

 iored, and (6) to clear up some matters concerning the interpretation 

 oihe data presented by them. We regret, therefore, that their second 

 cumunication 16 not only fails to contribute to these desirable ends but 

 irroduces other errors, some misleading quotations and statements, and 

 rrch wholly irrelevant discussion. 



It therefore seems quite useless, as well as personally undesirable to us, 

 tcontinue this discussion by commenting further on their second publica- 

 tii. For the convenience of the reader who may, if he cares to take the 

 tiie, verify the statements from the original papers, we may add this sum- 

 rrry. 



1. A note by Warner and Edmond in a poultry publication appeared a 

 nnth after the work of Lawrence and Riddle was published. It dealt 



Warner and Edmond, J. Biol. Chem., 1918, xxxiv, 171. 



