WORK UNDER PRESSURE AND IN GREAT HEAT 385 



an answer was that of von Schrotter and his colleagues, based 

 in part on theoretical considerations suggested by Zuntz, and 

 evidently to a large extent correct. In many points, however, 

 it seemed to us that von Schrotter's conclusions were open 

 to criticism. Practical experience, for instance, seemed to show 

 that it takes far longer than he believed for the human body 

 to become saturated with nitrogen in compressed air, and a 

 correspondingly longer time to become desaturated. Similar 

 criticisms applied to the conclusions of Hill and his colleagues 

 on this subject. 1 



It was evidently necessary to make further experiments, 

 and these were rendered possible in England by the gift to 

 the Lister Institute by Dr. Ludwig Mond, F.R.S., of a large 

 experimental steel chamber capable of comfortably taking a 

 number of animals or several men. In this the experiments 

 were carried out by Dr. A. E. Boycott, of the Lister Institute, 

 Fellow of Brasenose College, Oxford, and Lieutenant Damant, 

 the naval officer who, as already mentioned, was also engaged 

 in experiments on himself and others in deep water at sea. 

 For the experiments on animals goats were selected, as we 

 were convinced from the outset that small animals, in conse- 

 quence of their rapid circulation, were useless for our purpose. 

 Indeed, very small animals showed no symptoms whatsoever 

 after exposures from which rapid decompression killed goats 

 with certainty, and a fortiori would have killed men. With 

 long exposures to high pressures the risks to be guarded 

 against on decompression are undoubtedly still greater in men 

 than in goats. 



Several hundred decompressions of goats, men, and other 

 animals have been carried out during 1906 and 1907 by Boycott 

 and Damant. In the time available I cannot, however, give 

 more than an outline of some of the results. 



In the first place it was found that, with equal conditions 

 as regards decompression, the symptoms observed in goats 

 increased in danger and severity as the duration of exposure 

 increased up to at least two hours or perhaps somewhat 

 more. This is illustrated in Table III., showing some of the 

 results : 



1 Journal of Hygiene, vol. iii. p. 436, 1903 ; Proceedings of the Royal Society, 

 vol. Ixx. p. 455, 1903 ; vol. lxxvii. p. 442, 1906 ; vol. Ixxix. p. 21, 1907. 



