NOTES AND ABSTRACTS. 



639 



mesophytic form was sometimes thicker than the xerophytic form of 

 1909, but the xerophytic form of 1911 was correspondingly increased. 



The vessels of the stem tend to be larger in the mesophytic, but 

 more numerous in the xerophytic form. In the latter the walls of 

 vessels and fibres are thicker. There is a more woody cylinder, an 

 increase in mechanical tissue and in cork, as well as a slower growth in 

 the xerophytic forms. 



The paper is of great importance not only to ecologists, but as 

 bearing on the theory of adaptations and of the general origin of plant - 

 species. — G. F. S. E. 



Elms in Illinois, What is the Matter with the ? By S. A. Forbes 



{U.S.A. Ex'p. Stn., Illinois, Bull. 154; Feb. 1912; 6 plates, 4 figs.).— 

 An affection of the elm tree is now prevailing over a large part of 

 Southern Illinois, similar to one that destroyed many elms in the 

 central part of the state thirty years ago. It is first noticed in early 

 summer; the leaves cease their growth, turn brown, and fall. This 

 is followed by the death of the branches ; usually the higher branches 

 are first affected, but the whole top soon goes, and in a year or two 

 the tree is dead. The smaller terminal roots die and dry up pro- 

 gressively, the process extending to the larger roots and the base 

 of the trunk. The disease and death of the tree is frequently 

 accelerated by the larvae of the many insects known to attack the elm. 



The author points out that, although care and attention are always 

 given to the various fruit trees, the shade and forest trees are more 

 often left to^ shift for themselves, and if more care was exercised 

 in pruning, feeding, and protecting generally, relieving them from 

 the attacks of insects and surgically treating them to heal the wounds 

 they have made, far fewer dead elms would be found. — V. G. J. 



Exportation of Plants, &c. : Surtlmary of Regulations {Bd. 

 Agr., Misc. Puh. No. 13; 1912). — A useful summary of the import 

 regulations in various countries trading with Great Britain concerning 

 plants, seeds, and so on. — F. J. C. 



Ferments, Concerningr the Oxydizing". By Oh. Bernard and 



H. L. Welter {Ann. Jard. Bot. Buit. ser. ii. vol, x. pt. i. pp. 1-58; 

 1912). — ^^The present communication is of a preliminary nature and 

 chiefly concerned with an account of the methods employed. It con- 

 sists of two parts, of which the first deals with the methods used for 

 indicating oxydizing ferments in general, whilst the second section is 

 concerned with the oxydizing ferments of the tea-plant in particular. 

 The ferment, which has been called ''oxydase," had already been 

 studied by Ohoda't and Bach, who showed that this is not a simple 

 body, but that it consists of (1) a peroxydase /3, and (2) a peroxide. 



In the case of the tea-plant the present authors find that a per- 

 oxydase, which is a substance with a constant and clearly expressed 

 catalytic action, is to be met with in all parts of the plant. On the 

 other hand, an oxydase does not occur as a staple and constant body. 



