932 



SCIENCE 



[N. S. Vol. XXXVIII. No. 991 



that its poisonous principle is a substance 

 free from proteid or only secondarily com- 

 bined with it." 



No local eifects were observed at the point 

 of injection of Gila monster venom, and no 

 curare-like action was noted. No marked 

 changes in the clotting time of the blood of 

 animals under the influence of Heloderma 

 poison were found. 



These studies confirm, in the main, the in- 

 vestigations of Van Denburgh and Wight. 

 Perhaps the principal difference in the two 

 series of observations is regarding changes in 

 the clotting time of the blood. The present 

 investigators report no observed change in 

 clotting time, while Van Denburgh, in pig- 

 eons subjected to Heloderma venom, found 

 the blood firmly clotted in the auricles while 

 the heart was still beating, and Van Den- 

 burgh and Wight observed that a primary 

 shortening in the clotting-time was often fol- 

 lowed by a complete loss of coagulability. 



The results set forth in this volume by Leo 

 Loeb and his collaborators constitute a valu- 

 able addition to our knowledge of reptUe poi- 

 sons. One can not but feel, however, that 

 these results would be more readily available 

 if given in much less extended form, nor 

 need one be an emotionalist to doubt whether 

 these results justify the experimental injec- 

 tion of venom into " more than 360 warm- 

 blooded animals " in addition to many cold- 

 blooded ones. 



John Van Denburgh 



San Feancisco, Cal. 



SPECIAL ABTICLES 



anatomy as a means of dugnosis of spon- 

 taneous plant hybrids 

 In the genetical studies, which have assumed 

 so large and justly prominent a position in bio- 

 logical work during the past few years, exter- 

 nal characters have been investigated almost 

 exclusively. It has in fact been quite generally 

 assumed that plants which resemble one an- 

 other externally either belong to the same 

 species or are at best only varieties of the 

 same species. Nevertheless it is true that the 



geneticist has often found it necessary, in his 

 work, to secure by continued cultivation, 

 " pure lines " of the plants he uses in his 

 breeding investigations. 



The intention of the present communica- 

 tion is to indicate that spontaneous hybrids 

 are of extremely common occurrence either 

 identical in appearance with recognized species 

 or varying so slightly and constantly over wide 

 areas from the norm, that they are recognized 

 as merely varietal modifications of recognized 

 species. They can often nevertheless be clearly 

 diagnosed as hybrids by the investigation of 

 their internal anatomy both vegetative and 

 reproductive. The full data of these obser- 

 vations, accompanied by the necessary illus- 

 trations, will be published elsewhere. 



It will be convenient to consider first the 

 case of identical external structure covering 

 profound differences in internal organization. 

 In the course of anatomical experimental 

 investigations, carried on in the laboratories of 

 plant morphology of Harvard University, on 

 some of the lower amentaceous Dicotyledons, 

 specially directed towards the elucidation of 

 the hitherto unrecognized but highly impor- 

 tant relation of wood rays to genetical and 

 phylogenetic sequence, material of Betula 

 ■pumila, from the Arnold Arboretum of Har- 

 vard University, diagnosed as such both by 

 the Arnold Arboretum and the Gray Her- 

 barium, showed profound differences in organi- 

 zation from wild material of the same species, 

 secured from widely separated localities in the 

 eastern United States and Canada. Vegeta- 

 tively the Arnold Arboretum specimens pre- 

 sented striking aggregations of wood rays in 

 segments of the woody cylinder, such as are 

 characteristic of the more primitive birches 

 and alders, and in this respect presented a 

 marked contrast to normal B. pumila, where 

 rays of this type can not be said to occur. 

 These peculiarities suggested its hybrid origin 

 and the reproductive structures of the abnor- 

 mal material were investigated for evidence 

 for or against this hypothesis. Male cones 

 examined early in March showed in the sporo- 

 genous regions of the anthers large areas of 

 abortive spore-mother cells. Late in April it 



