284 



The Influence of Increased Barometric Pressure on Man. No. 3. 

 — The Possibility of Oxygen Bubbles being set free in the Body. 



By Leonard Hill, F.E.S., and M. Greenwood, Jun., M.E.C.S., Eesearch 

 Scholar of the British Medical Association. 



(Eeceived January 26, — Eead February 7, 1907.) 



The avidity of the tissues for oxygen is such that this gas has never been 

 regarded as a factor in the production of decompression symptoms with 

 respect to the formation of bubbles. 



Bert's (1) analyses of the gas set free in the hearts of dogs rapidly decom- 

 pressed from 10 atmospheres gave — 



Per cent. C0 2 . Per cent. 2 . Per cent. N 2 . 



(1) 15-2 - 2-0 82-8 



(2) 15-9 84-1 



(3) 20-8 a trace 79'2 



v. Schrotter and his colleagues (2) found a higher percentage of oxygen in 

 similar analyses — 



Per cent. C0 2 . Per cent. 2 . Per cent N 2 . 



(1) 4 dogs yielded 471 15-31 79-98 



(2) „ 12-45 7-18 80-37 



Leonard Hill and C. Ham (3) killed rats by rapid decompression from 

 -f 10 atmospheres, or more, and, cutting up their bodies under a funnel filled 

 with acidulated water, obtained the following results : — 



Per cent. C0 2 . Per cent. 2 . Per cent. N 2 . 



(1) 10-7 2-1 87-2 



(2) 16-0 4-0 80-0 



Hill and Macleod (4) submitted frogs and toads to 20 atmospheres of 

 oxygen (Brin's oxygen, containing 93 — 95 per cent. 2 ) for five minutes, and 

 rapidly decompressed them. They found that the animals were convulsed 

 and enormously distended with gas. In the case of mice submitted to 

 10 atmospheres for five minutes and rapidly decompressed, no such distension 

 was observed, but the animals went into tetanic convulsions. These convul- 

 sions could be excited by a touch, the mice usually recovering and appearing 

 normal on the following day. Mice killed in the convulsive state showed, 

 here and there, a few bubbles in the vessels, some being found, on microscopic 

 examination, in the central nervous system, distending the capillary 



