May 24, 1918] 



SCIENCE 



517 



leys to render them immune to hay fever is 

 now under way and the serums prepared from 

 the black walnut pollen are the ones most 

 used. It is expected that by this means the 

 spring type of tlie malady can be largely elimi- 

 nated in those districts. A more direct method 

 would be to remove the trees, or, better yet, to 

 graft the tops over to English walnut, which 

 rarely, if ever, causes hay fever. By this latter 

 method the beautiful and stately trees along 

 the highways and in the parks could be pre- 

 served, but it would doubtless be diflSeult to 

 bring about unanimity of action. 



The relation of the eastern black walnut to 

 hay fever should now be determined since that 

 species is closely related botanically to our 

 western form. It may also be pointed out that 

 perhaps the most significant result of our 

 stndies, which cover the region from the 

 Eocky IVIountains west, is the discovery that 

 hay fever is here produced by an almost en- 

 tirely different flora from that which causes it 

 in the eastern states and in Europe, and that 

 the exact species involved must be determined 

 in each case before treatment for immunity is 

 undertaken. Botanical surveys and clinical 

 tests have been carried on by Dr. Selfridge and 

 the writer in order to determine the most im- 

 portant species for each district and these will 

 be continued as opportunity offers. 



H.\r\t:y Monroe Hall 

 Department of Botant, 

 University op California 



the canons of comparative anatomy 

 In a recent number of this journal' Pro- 

 fessor E. C. Jeffrey uses " an article on the 

 vessels of Gnetum in the January number of 

 the Botanical Gazette " as a " flattering testi- 

 monial " to the soundness of what he has called 

 the canons of comparative anatomy and at 

 the same time (to modify his pun) as an 

 illustration of poor marksmanship in the use 

 of those canons. As the author of that article 

 and as a firm supporter of those canons, I am 

 glad to offer my work as a testimonial to their 

 soundness and to their effectiveness in ana- 

 tomical offensives. But, according to Profes- 



1 Science, N. S., Vol. XLVII, No. 1214. 



sor Jeffrey, my marksmanship was defective 

 because I stated — and in so doing showed 

 " surprising ignorance " — that the vessels of 

 Gnetum are different from those of angio- 

 sperms. Aside from the fact that this state- 

 ment does not involve the use of the canons 

 at all, the whole theme of the article was that 

 the same type of vessel has been evolved in 

 Gncialf's and angiosporms in entirely different 

 ways. On page 90 for example I wrote: 



The possession of vessels by the two groups 

 ... is to be used as a remarkable illustration o£ 

 development by different plants of the same highly 

 specialized structure. 



Again on page 89 after speaking of the 

 perforation of the Gnetalean vessel I said: 



We have also seen that the similar single large 

 perforation of the angiosperm vessel, etc. 

 Professor Jeffrey seems to have misunderstood 

 what was in my mind because of my state- 

 ment that the vessel of Gnetum is like the 

 highest angiosperm type except that as a rule 

 it exhibits a narrow border. Yet every anat- 

 omist will agree that this statement is abso- 

 lutely correct because the highest type of 

 angiospermic vessel has no border on its per- 

 forations. Of course every anatomist knows 

 that the perforations of many angiospermic 

 vessels do show a border as do those of Gnetum, 

 but these are not of the highest type. 



It appears, therefore that our modern scien- 

 tific promulgator of canons is in certain re- 

 spects remarkably like his ecclesiastical pre- 

 decessors. "W. P. Thompson 



ALBINO TURKEY BUZZARDS 



In a recent issue of Science' there appeared 

 an interesting note on the supposed occur- 

 rence of albino turkey buzzards {Cathartes 

 aura aura) in Mexico, to which Mr. E. W. 

 Nelson has called the writer's attention. This 

 was based on the account of white " Carrion 

 Crows " given by Captain William Dampier 

 in his "First Voyage to the Bay of Cam- 

 peachy." That Dampier mentions these white 

 birds as of more or less common occurrence 

 in that locality at once raises a doubt of their 

 identification as turkey buzzards; and this 



1 Gudger, Science, N. S., Vol. XLVII., No. 1213, 

 March 29, 1918, pp. 315-316. 



