October 20, 1911] 



SCIENCE 



513 



is, there would result a quantitative division 

 of the material representing the character in 

 .question. This brings us back, at least so far 

 as certain characters are concerned, squarely 

 to the position taken by Morgan last year in 

 his paper : " Chromosomes and Heredity " 

 (Amer. Nat, 44: 449^96). 



While the hypothesis there presented, in- 

 cluding the proposition that the plane of di- 

 vision of homologous chromosomes may be at 

 any angle to the plane of union and the as- 

 sumption that a certain quantity of the mater- 

 ial representing a character must be present in 

 order that the character develop, will doubtless 

 account for the results (ratios) obtained in 

 F, of a cross, it certainly will not account for 

 the purity of extracted recessives and domi- 

 nants as exhibited hy their behavior in Fj and 

 later generations. To overloole this is to neg- 

 lect the fundamental part of Mendelism. 



A hypothesis that does not explain how ex- 

 tracted recessives can breed true generation 

 after generation without the production of so 

 much as a single individual having the domi- 

 nant character will hardly be accepted by 

 present-day students of genetics. 



E. A. Emerson 



HIBERNATION 



To THE Editor op Science: The Popular 

 Science Monthly of October, 1910, published 

 an article of mine entitled " The Natural His- 

 tory and Physiology of Hibernation," pp. 

 356-364. Since this article appeared some ad- 

 ditional facts, in natural history, have been 

 brought to my notice as well as some errors 

 bearing on this subject. It is the purpose of 

 this letter to note the former and to correct 

 the latter. 



On page 359 will be found the sentence: 

 " Many butterflies and moths hibernate in the 

 perfect state as well as in the form of imagos, 

 but not in the larval state (?)." The correc- 

 tion here is that "pupa" should be read in- 

 stead of "imagos." In the latter part of the 

 same sentence, "but not in the larval 

 state ( ?) " the statement is wrong, for several 

 butterflies and a great many moths hibernate 

 in the larval state, notably the Noctuidse and 



Arctiidse, consequently the query mark 

 should be abolished. 



Again the statement is made, " Insects 

 which hibernate do not pair until spring and 

 bees do not hibernate at all." This sentence 

 is not quite full enough and demands more 

 detailed information or additional light on the 

 subject. All our wild bees, wasps and some 

 others pair in the autumn and the fertile fe- 

 males hibernate. Hive bees, on the other 

 hand, pair in the spring and do not hibernate. 



The statement will be found on page 360: 

 " but curiously enough no case [hibernation] 

 is known among birds." I must still hold to 

 this notwithstanding the following account, 

 which may interest your readers, furnished to 

 me in a private communication, by Mr. C. W. 

 Nash, biologist to the Ontario government. I 

 quote in full : " I have found evidence (of a 

 sort) which leads me to believe that the 

 Purple Martin and Chimney Swdft may at 

 times become partially dormant and I have 

 recently received from an eye-witness an ac- 

 count of the cutting down of a hollow tree 

 near Peterboro, in the month of January, 

 many years ago ; this tree is said to have con- 

 tained hundreds of swallows in a dormant 

 state, some of which were revived. I have the 

 names of other witnesses of this curious inci- 

 dent and am looking them up." 



In support of this suggestive phenomenon 

 one can say that we do not know what part of 

 the world the Chimney Swift does migrate to 

 for the winter but it would be well to remem- 

 ber also that we are equally ignorant of the 

 path the Arctic Tern takes to and from its 

 winter and summer homes, 11,000 miles 

 apart! We are still lamentably ignorant of 

 a great many things about birds. 



Mr. Nash supports the statement on page 

 360 that a low temperature was not the only 

 cause of hibernation. He experimented with 

 Black Bass and found that when the fish were 

 " kept in a warm room they ceased to feed at 

 the end of October and resumed again in 

 March, though they never became dormant — 

 in fact were just about as active during the 

 winter as at any other time, though in nature 

 I do not think they are so." I trust that these 



