May 18, 1917] 



SCIENCE 



483 



tral nervous system from the labyrinth." 

 Crum Brown's statement of the function of 

 the semicircular canals was " the perception 

 of the change of aspect of the head in space." 

 This statement has stood the test of criticism 

 and one usually is aware of the change of 

 aspect of the head in space. 



The easy-going husband and the nagging 

 wife find their counterpart in the ventricles 

 and the auricles of the heart, p. 257. A decla- 

 ration of independence on the part of either 

 husband or ventricle leads to domestic 

 infelicity. 



On the whole, the book fulfills its particular 

 purpose better than any other with which I 

 am familiar. Writing such a book is a par- 

 ticularly difficult task, and the author has 

 succeeded better than most. There are many 

 new diagrams of unusual clearness. 



F. H. Pike 



Depaktment of Physiology, 

 Columbia Univeesity 



GOODALE'S EXPERIMENTS ON GONA- 

 DECTOMY OF FOWLS 



It has long been known that the removal 

 of the testes of the male fowl does not affect 

 materially the complete development of the 

 secondary sexual characters of the cock, al- 

 though a critical examination of the results 

 has been much needed. The change of the 

 hen's plumage into that of the cock, a change 

 that occasionally takes place in old age, or 

 when the ovary has become diseased, is also 

 a matter of record, but the evidence for this 

 has been rather anecdotal than detailed. 

 Both changes have now been carefully studied 

 by Goodale in a series of carefully planned 

 experiments carried out through a series of 

 years, mainly at the Station for Experimental 

 Evolution of the Carnegie Institution. The 

 results^ have been published recently by 

 the Carnegie Institution. The excellent 

 colored drawings that illustrate the results 

 greatly enhance their value. 



1 " Gonadeetomy in Eelation to Secondary Sex- 

 ual Characters of Some Domestic Birds," H. D. 

 Goodale, Carnegie Institution of Washington, 1916, 

 No. 243. 



The operation was made on Rouen ducks as 

 well as on fowls (Brown Leghorns) and the 

 results are in agreement in all essen- 

 tial respects. Complete removal of the testes 

 either from very young, or even from older 

 birds, does not cause any lessening of second- 

 ary sexual plumage, although in a few points 

 the capon differs in plumage slightly from the 

 normal cock and in a few minor points also 

 other than plumage. The complete removal 

 of the ovary of the birds is an extremely diffi- 

 cult operation and is rarely entirely success- 

 ful. Failure to remove all of the tissue gives 

 an opportunity for regeneration of the gland, 

 which completely nullifies the attempted ex- 

 periment. When removal of the ovary was 

 complete (as shown by subsequent dissection) 

 the duck and hen assumed the male plumage. 

 When the very great differences in the plum- 

 age of the Brown Leghorn hen and cock and 

 of the Eouen duck and drake are recalled, ' 

 the change is startling; for it involves not 

 only the transformation of the brown plumage 

 of the hen into the brilliant red and black of 

 the cock, but involves likewise a change in 

 the shape of many of the feathers, notably 

 those of the hackle, back, saddle and shoulder 

 as well as minute details in the barbules. 

 Goodale exhibited such a cock-feathered hen 

 at the Christmas meeting of the ISTaturalists, 

 as well as one case in which the testes had been 

 removed from a young cock and an ovary en- 

 grafted in their place. The presence of the 

 latter had prevented the cock, when adult, 

 from developing the characteristic male 

 plumage. He resembled a hen in essentially 

 all plumage characters. 



Into the details of the work it is not pos- 

 sible to enter here — details that involve the 

 effect of incomplete gonadeetomy, the possi- 

 ble influence of other organs in the neighbor- 

 hood of the gonad, the relation between the 

 juvenile plumage and that of the adult fe- 

 male, and in the case of the ducks the effect 

 of gonadeetomy on the nuptial and eclipse 

 plmnage. Several results here obtained are 

 entirely new and a number of problems raised 

 heretofore unsuspected. 



