COMPRKSSKn AIR PIIKNOMKNA. Ill 



compressors in the engine room, and can be flooded with air as 

 desired. 



The pathology of this disease is very obscure, and there are 

 a number of theories as to the way in which the air acts upon 

 the system. One theor>' is that it is caused by excess of 

 oxygen in the tissues; another that it is excess of nitrogen, 

 and one French physician claims to have demonstrated the 

 presence of bubbles of nitrogen in the blood of a caisson 

 worker. 



Another theory is that owing to the great waste of tissue 

 from the active oxygen, the system is unable to eliminate this 

 waste and a poisoned condition is induced. It is well known 

 that the specific gravity of the urine is very high in cases 

 of " bends." 



Still another idea is that congestion of blood in the internal 

 organs is the prime cause, and in this connection it may be 

 said that a post mo?iem examination of a patient has dis- 

 closed a necrosed and crumbly condition of the spinal cord. 



Full blooded and fleshj^ men are much more readily 

 attacked by this disease than those having little adipose tissue. 



In spite of the strain upon the lungs, there is a case on 

 record of a man with a large cavity in one lung, who 

 improved under caisson work, and the writer has heard of 

 cases of asthma which improved under it ; also of men prone 

 to rheumatism who never suffered while in compressed air ; 

 and who were in time cured by long continued work in it. It 

 may be said, however, that most diseases are greatly aggra- 

 vated by compressed air, but a strong constitution can be 

 safely exposed to it daily for months or years, if great care is 

 taken to put no strain upon the system while in normal air, 

 and to considerably increase the time given to sleep. 



Baldness is greatly benefitted by compressed air. The 

 writer has in mind two young men, who upon beginning work 

 were almost bald, but after about a year of tegular work in 

 high pressure had quite a thick growth of hair. 



The activity of the oxygen is strikingly shown when 



