

7A 



NATURE 



[October 14, 1915 



a considerable interval of time elapses between 

 decompression and the onset of symptoms due to 

 bubble-formation. It is commonly fifteen or 

 twenty minutes, and often far more, before the 

 appearance of symptoms caused by bubbles after 

 rapid decompression frqm a high atmospheric 

 pressure. Sudden effects, such as those said to 

 be produced by bursting shells, are never ob- 

 served, however rapid the decompression may have 

 been. The formation of bubbles of sufficient size 

 to do any harm is evidently a process which takes 

 considerable time. A momentary decompression, 

 even if it were extreme, could scarcely, therefore, 

 have any serious effect. 



If, however, minute bubbles were formed, they 

 would rapidly disappear again when the moment- 

 ary wave of negative pressure had passed. 

 Abundant experience has shown that there is no 

 more rapid and certain means of treating the 

 symptoms due to bubbles than recompression. 

 When men who have come out of compressed air 

 are affected, they can be relieved by returning 

 them to the compressed air from which they 

 came, or placing them in a medical recompression 

 chamber provided for the purpose. As an in- 

 stance of the application of this treatment, a 

 recent case may be recorded of a naval diver who, 

 owing to some emergency, had returned to sur- 

 face suddenly, without carrying out the prescribed 

 regulations for safety. About twenty minutes 

 afterwards he became ill, lost consciousness, and 

 was apparently dying from bubble formation. In 

 accordance with the recommendations for dealing 

 with such a case, in the absence of a re-com- 

 pression chamber, his helmet was screwed on, 

 and he was then lowered to the depth from which 

 he had come. He recovered consciousness 

 rapidly, and was soon able to answer the tele- 

 phone, after which he was safely brought up, 

 with due precautions. In the case of a man ex- 

 posed only momentarily to decompression, the 

 remedy for bubble-formation is, of course, auto- 

 matically applied at once, since he returns at once 

 to the pressure from which he was decompressed. 



Recent investigations in this country have 

 shown that symptoms due to bubble-formation do 

 not occur unless the absolute barometic pressure 

 is diminished by more than half. Thus it is safe 

 to decompress rapidly from two atmospheres' 

 pressure to one, or from six to three ; and the 

 Admiralty regulations for safety from bubble- 

 formation in diving are based on this fact. Hence 

 a sudden diminution of pressure from normal to 

 half an atmosphere would not be dangerous, even 

 if the decompression were a prolonged one. The 

 momentary diminution observed by M. Arnoux 

 was, however, only 350 mm., or not quite half 

 an atmosphere. 



It appears, therefore, to be impossible to accept 

 the bubble theory of the action of bursting shells 

 in killing men without visible wounds or 

 mechanical injury. The newspaper accounts of 

 men being killed by bursting shells in some 

 sudden and mysterious manner, without wounds 

 or bruises, appear to be imaginary. The experi- 



NO. 2398, VOL. 96] 



ence of those who have been exposed to shell fire 

 does not, so far as the writer's inquiries go, lend 

 any support to these accounts. Neither poison- 

 ous gases nor any other known cause would 

 account for men being instantly killed without 

 mechanical injuries. An air-wave of sufficient 

 violence may doubtless -knock men over and in- 

 flict mechanical injury capable of causing death ; 

 but the actual fatal injuries caused by shells |^ 

 appear to be almost all due to fragments of metal ':'■, 

 or of stone or other material set in motion by the \\ 

 explosion. J. S. Haldane. j! 



DR. J. MEDLEY WOOD. 



WE record with regret the death, on August 

 26, at the Botanic Gardens, Durban, in 

 his eighty-seventh year, of the veteran director of 

 the Natal Herbarium, Dr. John Medley Wood. 

 Dr. Medley Wood was a native of Mansfield, 

 Nottinghamshire, and had resided in Natal for 

 sixty-three years. 



Before his appointment as* curator of the Natal 

 Botanic Gardens in 1882 he practised for a time 

 as a solicitor, and then went trading to Zululand, 

 afterwards devoting himself to farming. His 

 home was then at Inanda, where he spent some 

 ten years, and besides undertaking experiments 

 in the cultivation of arrowroot and castor oil he 

 interested himself in the local flora, and contri- 

 buted large and important collections of Natal 

 plants to Sir Joseph Hooker for the National Her- 

 barium at Kew. His activities in this latter direc- 

 tion were naturally stimulated on his appointment 

 to the Gardens. Not only did he continue to 

 enrich the collections at Kew, but he founded and 

 gradually built up the very valuable Herbarium 

 of Natal plants at Durban, which is a model of 

 what a colonial herbarium should be. 



When Dr. Medley Wood was appointed curator 

 of the Natal Garden in February, 1882, by the 

 Durban Botanic Society, the condition of the 

 garden was by no means flourishing, but as 

 funds allowed he was not long in restoring it 

 to a condition of beauty and usefulness. The 

 value of his work was so far appreciated that the 

 Government grant towards the upkeep of the 

 garden and the maintenance of the collections 

 was gradually increased, and in 1902 the new 

 building for the Herbarium was completed. In 

 1909 the Herbarium collection consisted of some 

 43,000 mounted and classified specimens. Medley 

 Wood's publications on the Natal flora form valu- 

 able contributions to botanical science. In 1886 

 he published an analytical key to the orders and 

 genera of Natal plants, but the most important 

 of his works is that entitled "Natal Plants," of 

 which six volumes have been published, the first 

 part, consisting of fifty plates with descriptions, 

 having appeared in 1898. Other useful publica- 

 tions include his " Handbook to the Flora of 

 Natal" (1907) and a "Revised List of the Flora 

 of Natal" (1908). His "Guide to the Trees and 

 Shrubs in the Natal Garden," published in 1897, 

 giving dates of planting, is a valuable record of 



