■86 NATURAL SCIENCE. Feb., 



of the root-cap. He also finds, as Wiesner proved ten years ago, that 

 the curvatures do not result from simple contact, and from several 

 experiments adduces strong evidence that they are the result of an 

 injury to the growing point. Thus they follow a small injury which 

 -extends to the growing point but fails to take place even after exten- 

 sive injury in which the growing point is not involved. Some of the 

 most interesting cases cited are those which show that the stimulus to 

 a 'curvature may remain latent during an artificial suspension of 

 growth. It was found that roots which have been wounded may 

 have their growth in length stopped by confinement in plaster casts 

 for several days, and that traumatropic curvature still takes place 

 when they are released and growth is resumed. 



Finally, the author claims that the experimental evidence 

 adduced justifies the belief that the growing point of the root is 

 sensitive, and that its irritation induces the curvature in the zone of 

 rapid growth behind the root-tip. Such results are comparable with 

 those obtained in the study of curvatures induced by the stimulus of 

 light and gravity. For instance, in the case of the cotyledons of 

 grasses the tip has been shown to be most sensitive to the directive 

 action of light, the stimulus being transmitted from the tip to the 

 lower part, where, after an interval of time, the corresponding curva- 

 ture is observed. 



Sir Henry Howorth's Complaint. 



In a letter, printed in our last issue (Natural Science, vol. vi., 

 p. 71), Sir Henry Howorth complained that two specialists, who are 

 both distinguished men and both officers of the same museum, have 

 within a year of one another published two volumes on reptiles in 

 which the same forms have " not merely different names but are put 

 in different genera." We find that Sir Henry Howorth is quite right 

 in his facts. Indeed, we are assured by those who know that some sixty 

 per cent, of the species are called by different names in the two 

 works. Certainly it is a matter for regret that divergence of opinion so 

 extreme should exist between two high authorities from whom the 

 public may expect guidance ; and the public will be still more 

 puzzled to find that in the case of the British Museum Catalogue the 

 same authorities are in amiable conjunction, the one as author the 

 other as editor. But it may be pointed out that the fact of both 

 being officers of the same museum has nothing to do with the case. 

 In the official Catalogue the two agree ; but the trammels of 

 office must not hinder free expression of opinion on scientific matters, 

 even on specimens contained in the museum, when that expression is 

 made in an unofficial and purely private publication, such as the 

 Biologia Centrali-A mevicana. 



On the general question of divergent nomenclature we think 

 that Sir Henry Howorth's complaint is exaggerated. The whole 



