Apeil 22, 1910] 



SCIENCE 



637 



endocarp. Laymen have assumed that these nuts 

 are hybrids between the walnut and hickory, i. e., 

 the trees bearing tliem were true walnuts while 

 the pollen involved in fertilization was from 

 neighboring hickories. In face of known morpho- 

 logical facts this is impossible. The author ex- 

 pects to make a study of this matter from all 

 view points. The purpose of this preliminary 

 statement is chieiJy to call attention to these 

 plants and request any one having information of 

 similar ones to kindly report to him at Washburn 

 College, Topeka, Kans. 



Studies upon Oxidases: H. Hasselbrins and C. 



L. Alsberg. 



The study is a by-product of the investigations 

 still in progress of a disease of cabbages and 

 spinach resembling in some respects the mosaic 

 disease of tobacco. As in the latter there seems 

 to be an increase in the oxidizing power of the 

 juice of the diseased areas. By Woods this phe- 

 nomenon was referred to an increase in oxidase 

 content. To the authors this did not appear to be 

 the only explanation conceivable. It was possible 

 that the oxidase content was only apparently in- 

 creased, the seeming increase being in reality due 

 to a decrease of anti-oxidase. The anti-oxidases 

 were therefore studied. It was found that egg 

 albumen and blood serum inhibit these plant oxi- 

 dases and that this inhibition can be prevented if 

 the albumen or serum is first treated with weak 

 acid. It was further found that the addition of 

 coagulable protein to a plant extract varies greatly 

 the ease with which the oxidase is destroyed by 

 heat, probably because of the inclusion of the 

 enzym in the clot. This may account for the 

 fact that plant oxidases are less readily destroyed 

 by heat than animal oxidases, for plant extracts 

 contain as a rule less coagulable protein than 

 those from animal tissues. These observations led 

 to an investigation of oxidase zymogen. Woods 

 made the very remarkable discovery that a plant 

 extract which has lost its oxidizing power as the 

 result of boiling may recover that power on 

 standing some hours. Woods thought that the 

 enzym was destroyed but the more resistent 

 zymogen remained forming fresh enzym subse- 

 quently. We found that if a heated extract be 

 centrifugated right after heating, and the clear 

 liquid pipetted off from the coagulum, the clear 

 liquid did not acquire any oxidizing power on 

 standing, while that portion of the liquid contain- 

 ing the coagulum did recover its oxidizing power. 

 It is possible, therefore, that we have to deal not 

 with a zymogen but with the inclusion of the 



enzym in the clot and its subsequent leaching out 



on standing. 



Some Teratologioal Features of the Coniferce: 



Robert Boyd Thomson. 



A new classification of the conifers, the out- 

 come of recent research, has been suggested by 

 the writer. In this the Taxaceffi and the Arau- 

 carinete are associated, the group being character- 

 ized by a simple megasporophyll. The Abietineae, 

 TaxodinefB and Cupressineae constitute the second 

 group. These exhibit complexity in the structure 

 of the seminiferous scale. Teratologieal features 

 so far reported are practically confined to the 

 latter, the diplosporophyllous group. These in- 

 clude androgyny, prolification or percrescence of 

 the axis, and modification of the seminiferous 

 scale, the latter often being replaced by a leafy 

 shoot. By many the last of these features, espe- 

 cially, is considered as affording evidence of the 

 brachyblast character of the ovuliferous scale. 

 The writer's observations on numerous hermaphro- 

 dite cones of Pseudotstiga mucronata confinns and 

 extends this conception. In the aplosporophyllous 

 series, on the other hand, certain teratologieal 

 features have been found that afford confirmation 

 of the simplicity of the cone scale. 

 On the Distribution and Origin of Bay Tracheids 



in Pin/us Strobus and P. resinosa: W. P. 



Thompson. 



Kay tracheids are characteristic features of 

 certain coniferous woods, notably the pines. A 

 detailed study of their regional distribution in a 

 soft and a hard pine (P. Strobus and P. resinosa) 

 shows their virtual absence from such primitive 

 places as the stem and root of the seedling, the 

 young branch of the adult and the axis of the 

 seed cone. Their shape and character on first 

 appearance, their mode of development at the 

 cambium, and certain peculiarities of their adult 

 form, demonstrate that they originate from trach- 

 eids. These, in the course of specialization, become 

 shortened, radially arranged and intimately asso- 

 ciated with the parenchyma cells of the ray. Their 

 extreme specialization is reached in the short but- 

 tressed cells of the hard pines. 



The knowledge of their distribution and origin 

 in the forms studied supplies a basis for a deter- 

 mination of their general phylogenetic significance. 



The following papers were read by title : 

 On the Organization and Reconstruction of the 



Somatic Nuclei in Podophyllum, peltatum: J. B. 



Overton. 

 Cleistogamy in the Genus Muhleniergia: Agnes 



Chase. 



