Mat 7, 1909] 



SCIENCE 



739 



brates. The difference in the results obtained 

 by the two methods has been so great that I 

 could not be induced to return to the former 

 method. The course of the second type has, 

 in its results, utterly outclassed that of the 

 first sort at all points, even in pure training 

 in observation, for observation must include 

 a conception of the adaptations in the phe- 

 nomena observed. Even students who plan 

 to study medicine are, I am sure, far better 

 prepared to study with intelligence human 

 embryology than if they had given their at- 

 tention wholly or chiefly to amniote embryos 

 in which the space relations of the organs are 

 so distorted by secondary influences. 



Material for the elementary cytological work 

 and the study of cleavage and gastrulation is 

 easy to prepare and also can readily be pur- 

 chased, and there is no difficulty, of course, 

 in obtaining frog embryos and larvffi. The 

 yolk in the earlier embryos necessitates care- 

 ful work in preparing sections, but, by avoid- 

 ing absolute alcohol and by using an oil that 

 does not make the yolk too brittle, good 

 preparations are readily obtained. The labor 

 of preparing sections of frog embryos and 

 larvse seems no greater than that of preparing 

 chick sections. At any rate, the labor is not 

 such as to lead one, in order to avoid it, to 

 choose less instructive material for study. 



Perhaps no clearer text-book has ever been 

 written than Marshall's " Vertebrate Embry- 

 ology." In spite of some inaccuracies, and of 

 not being up to date, it is still usable, but its 

 cost is considerable, and it contains more than 

 most introductory embryological courses can 

 cover. Holmes's volume, " Biology of the 

 Erog," gives insufficient treatment to the 

 embryology, and Marshall's little book, " The 

 Frog," is no more adequate on this side. 

 Morgan's "Development of the Erog's Egg" 

 is not adapted for an introductory embryo- 

 logical course. We greatly need an embry- 

 ology of the frog. A revision of Marshall's 

 chapters on this subject, and their publication 

 as a separate volume would well meet this 

 need. Were there such a volume obtainable, 

 one would not fear harm from the publication 

 of Lillie's " Development of the Chick," for 

 courses of each type would then have a satis- 



factory text-book and an unbiased choice 

 would be possible; but under present condi- 

 tions one does fear that the very escellenee of 

 Lillie's book will serve to perpetuate an un- 

 fortunate tradition and will delay the general 

 coming of embryological courses that are 

 a better preparation for general morphological 

 study. 



M. M. Metcalp 



THE COUNTRY BOY AGAIN 



In Science, February 12, in discussing in- 

 dustrial education, I made the statement that 

 with only 29 per cent, of our population actu- 

 ally living on the farm, with miserably poor 

 school facilities as compared with our city 

 population, this 29 per cent, furnishes about 

 70 per cent, of the leaders in every phase of 

 activity in this country. This statement was 

 quoted from memory and was in error to the 

 extent that I should have said 29 millions of 

 our population instead of 29 per cent. Dr. 

 Frederick Adams Woods, in Science, April 9, 

 quotes this statement and adds some criti- 

 cisms. 



First, I want to assure Dr. Woods that I 

 appreciate very fully the magnificent work 

 he did in his study of heredity in royalty. It 

 fell to my lot to review Dr. Woods's book, 

 and I found it one of the most interesting 

 treatises on heredity we have. He has dem- 

 onstrated, I think, beyond cavil, that " na- 

 tive ability and natural impulses of human 

 beings are as much a matter of heredity as 

 are any physical characteristics." 



The above quotation is from my review of 

 Dr. Woods's paper in my article on Mendel's 

 law, which will appear soon in Volume V. of 

 the American Breeders' Association. In that 

 review I say further: 



Prodigious effort has been made by the human 

 race to better its condition but this effort has been 

 wholly in the direction of improving the environ- 

 ment. While Dr. Woods has shown that it is 

 really an unimportant factor in determining 

 natural impulses and native ability, it is true 

 that when environment is unfavorable it may pre- 

 vent the development of natural tendencies or may 

 warp them, and it may also result in great 



