330 



SCIENCE 



[N. S. Vol. XXXIII. No. 844 



(showing that this structure depends upon 

 two gametic characters, instead of one as 

 hitherto supposed), and with comb-lop (show- 

 ing that tlie direction of the lop is not appar- 

 ently inherited). Chapters X. and XI. deal 

 with various phases of the inheritance of 

 plumage, color and pattern. A general gametic 

 formula for poultry coloration is worked out 

 and evidence presented in its favor. Data are 

 given regarding the inheritance of certain 

 pattern types. 



The last chapter is devoted to a general dis- 

 cussion of certain theoretical matters of prime 

 importance. Stress is l^id upon the possible 

 significance of " inhibit'ors " in addition to 

 " determiners " in ontogeny. The " principle 

 of imperfect dominance " is discussed at 

 length. One fancies that here is where the 

 greatest disagreement will be found amongst 

 students of the subject. The reviewer, frankly, 

 is unable to see that degree of heuristic worth 

 in this concept which the author seems to find. 

 It seems possible to account for all the facts 

 on which this concept rests in other ways, not 

 any the less in accord with Mendelian prin- 

 ciples. Virtually these facts amount to an 

 apparent failure of segregation. One may 

 safely say that practically all students of in- 

 heritance whose study involves a real, first 

 hand acquaintance with the living, breeding 

 organisms are deeply impressed with the 

 precision and definiteness of segregation 

 generally. When apparent exceptions to the 

 law of precise segregation occur one's zeal is 

 aroused to discover the cause. There is a wide 

 range of physiological factors beyond such 

 things as " imperfection of dominance " which 

 must be considered here (teste the work of 

 Tower and of Tennent, for example). Prob- 

 ably every one will admit that the data now 

 available do not permit any final conclusion as 

 to what are the primary factors involved in 

 causing apparent exceptions to Mendelian 

 principles, either in general or in particular 

 eases. What clearly are needed are more of 

 such extensive collections of definite experi- 

 mental data as are furnished in the work 

 under discussion. We may well observe that 

 caution expressed by Robert Boyle as an apol- 



ogy for not taking a more decided stand on 

 theoretical questions : " having met with many 

 things for which I could assign no probable 

 cause, and with some for which many differ- 

 ent ones might be alleged, I dare speak posi- 

 tively and confidently of very few things ex- 

 cept of matters of fact." 



Eaymond Pearl 



The Teaching Botanist. A Manual of In- 

 formation upon Botanical Instruction. By 

 William F. Ganong, Ph.D., Professor of Bot- 

 any in Smith College. Second edition. 

 Pp. 12 + 439, illustrated. New York, The 

 Macmillan Company. 1910. 

 At a time when the teaching profession is 

 being assailed on all sides with demands for a 

 practical education, and when the meaning of 

 " practical " is, in the main, materialistic, 

 those teachers in botany still committed to 

 ideals, but perhaps finding difficulty in har- 

 monizing them with the proper demands of 

 those seeking immediately useful training, 

 will find a champion in the author of " The 

 Teaching Botanist." Professor Ganong has 

 worked long and consistently with the avowed 

 purpose of trying to solve the problem of the 

 content and method of an elementary course 

 in botany. He may therefore be looked upon 

 by the teacher seeking guidance as among the 

 safest and surest. He would be the first to 

 disavow the claim that he has quite answered 

 the question to which his book is a large and 

 satisfying reply, but we do not hesitate to say 

 that he is far along on the right track. 



" The Teaching Botanist " in its present 

 form is called a second edition, but is very 

 largely a rewriting. On the side of informa- 

 tion, which the teaching botanist desires to 

 have respecting the materials with which he 

 deals, it has been brought down to date. The 

 results of actual teaching experience during 

 the last few years have been set down. In 

 this sense the book is practical, in some direc- 

 tions almost encyclopedic, and will stand in 

 good stead to one who is planning courses or 

 equipping a laboratory. This wiU be under- 

 stood to include also the matter of books, 

 which are well discussed, and of which a fuU 



