272 EXPERIMENT STATION RECORD. 



variation in regard to egg yield is practically the same at the end as at the 

 beginning of the work, namely from to approximately 250 eggs i^er hen i)er 

 year. " That is to say, after 9 years of selection with respect to egg production 

 the birds breed no truer to a definite type of egg production than they did at 

 the beginning. It will be i-ecognized by every stock breeder that this is an im- 

 portant fact to be taken into consideration in passing opinion on the value of 

 the method of breeding poultry which was tried in the experiment." 



When the average egg yield is considered year by year there is no evidence of 

 any increase in the egg pi'oduction of the individual, that is, by selective breed- 

 ing the average egg production has not been increased, and as a whole the 

 results show " that the quality of high productiveness can not be regarded as 

 any more a fixed characteristic of the station's strain of Barred Plymouth 

 Rocks now than it was at the beginning of the experiment." The author points 

 out that the records show no special change in the proportion of hens with very 

 low egg yield to high producers in the flock, there being relatively few of the 

 low egg producers at any time. Attention is called to the fact that the con- 

 clusions now presented differ somewhat from those presented earlier, oAving to 

 the fact that some sources of error have been found in the summaries previously 

 published. 



" The practical conclusion to be drawn from the results of this breeding 

 experiment seems to the authors to be clear. It is that the improvement of a 

 strain of hens in egg-producing ability by selective breeding is not so simple a 

 matter as it has been supposed to be. Nothing could be simpler than breeding 

 from high producers to get high producers. But if this method of breeding 

 totally fails to get high producers — in other words, if the daughters prove not 

 to be like the mothers in egg production — it can not fail to excite wonder as to 

 whether the simplicity of the method is not its chief (possibly its only) recom- 

 mendation. Anyone who makes a thorough, first-hand study of an extensive 

 selection experiment carried out, as was this one, by the so-called German 

 method without testing of the centgener power of the Individual organisms, 

 can not fail to be impressed, we believe, with the fact that the improvement of 

 a race by selective breeding is a vastly more complicated matter than it is 

 assumed to be by those who maintain that one need only to breed from the 

 best to insure improvement. The supposed ' facts ' of heredity on which the 

 practical stock breeder (working for utility points) operates are in very lai'ge 

 part inferences rather than facts. What is needed more than anything else for 

 the advancement of the stock-breeding industry in all its phases is an accumu- 

 lation of definite knowledge of the fundamental principles of the hereditary 

 process. All breeding oiierations must be based on the laws of inheritance in 

 organisms. The jn-actical stock breeder is able to work out the applications of 

 these laws for himself. What he most needs is broader and deeper knowledge 

 of the laws themselves. This knowledge must come from thoroughgoing, purely 

 scientific investigations." 



Poultry keeping for eg-g production, W. P. Brooks (Massachusetts Sta. Bui. 

 122, pp. 3-6.'i, figs. 9). — In this bulletin, which is designed as a guide to poultry 

 keeping for egg production, houses for growing birds and for laying stock, ques- 

 tions of breeds, incubation, and brooding, and the general management and feed- 

 ing of both chickens and laying stock are discussed. On the basis of personal 

 experience and experiments made at the station and elsewhere, a summary is 

 also presented of the 13 years' poultry experiments at the station, from which 

 the following conclusions are drawn : 



The regular use of condition powder is unlikely to increase the egg product 

 and is unnecessary as a means of insuring health. Cabbages given in modera- 

 tion are superior to cut clover roweu as winter food for egg x)roduction, but if 



