46 INHERITANCE IN POULTRY. 



line being longest. The sickle feathers (5) may belong to either row, so 

 far as the adult position indicates ; but, as growing feathers, they belong 

 physiologically to the middle series. The anterior row (A) is, at the same 

 time, the posterior row of tail coverts. The lateral feathers of this row are 

 the smallest, owing to a late and brief growth. The long tail of the Tosa 

 fowl is thus produced by the prolonged growth period of the middle row of 

 feathers including the sickle, together with the more median feather of the 

 anterior row. 



Cause of excessive growth of tail ; Cunningham 1 s experiments. The cause 

 of this prolonged growth of the median and sickle feathers is the crucial 

 point. The latest student of the subject, Cunningham (1903, p. 232), 

 quotes Mr. John Sparks as stating : "In order to ensure very great length 



of tail, the cocks ought to be kept on a perch and the tail-feathers 



should be pulled gently every morning." Cunningham adds: "My own 



experiments tend to show that this mechanical treatment of the 



feathers is the whole secret of the mystery." He describes in great detail 

 how he stroked the tail of one of two cocks daily ; the other not at all. 

 When a feather stopped growing he pulled it out. He concludes (p. 248) : 



In the cock whoss feathers were stimulated by pulling, growth did not go on at a 

 more rapid rate, but continued for a longer time and produced a longer feather. Thus 

 in cock A [not stroked] no growth took place after April i, and the maximum length 

 was 2 feet 4^ inches; while in cock B [stroked] growth continued till July 13, and the 

 maximum length was 2 feet 9^ inches. 



Half a page farther on Cunningham sums up thus : 



The long-tailed cock in its perfection, therefore, is neither a sport nor a breed, but 

 the product of artificial cultivation ; and the excessive growth of the feathers is the result 

 of stimulation applied to the individual. The more important part of the stimulation is 

 not the mere pulling of the feathers, but the extraction of it which causes the growth of 

 its successor. 



One can not but remark that Cunningham here contradicts himself. After 

 having laboriously pulled the feathers for over a year and found that the 

 feathers are stimulated by pulling, he states : " The most important part of 

 the stimulation is not the pulling but the extraction of the feather causing 

 the growth of its successor." Does Cunningham indeed think that, origi- 

 nally, by extraction of a feather its follicle was so stimulated that it there- 

 after produced feathers which neither ceased to grow nor molted and, 

 moreover, so affected the germ plasm as to produce a race with a tendency 

 toward excessive growth of feathers ? Certainly such a conclusion seems 

 past belief. 



Author 1 s experiments. To see what influence, if an} r , stroking the tail 

 feathers has upon their growth, I experimented upon two cocks. One 

 (No. 3, "Admiral Togo") was stroked twice daily by passing the feathers 

 of the middle and anterior row between the thumb and forefinger. The 



