282 ANNUAL OF SCIENTIFIC DISCOVERY. 



through thorn; whereas, increasing the pressure has the effect of 

 collapsing them, and therefore makes it more difficult to admit 

 the compressed air within the cavities of the ears. It frequently 

 occurs, however, from some abnormal condition of these tubes, 

 as when inflamed by a cold in the head, that neither of these 

 remedies will relieve the pain. To continue the admission of 

 compressed air into the lock, under such circumstances, would 

 intensify the suffering, and possibly rupture the tympanum ; 

 therefore the lock-tenders were particularly instructed to shut off 

 the compressed air at the moment anyone in the lock experienced 

 pain about the ears ; and then, if it could not be relieved by the 

 above means, the lock was opened, and the person was not per- 

 mitted to go through into the air-chamber. Sometimes 15 min- 

 utes were occupied in passing persons through the first time, after 

 which they usually had no further trouble from this cause. 



The fact that the depth penetrated by the air-chamber was 

 considerably greater than that hitherto reached in any similar 

 work, left me without any benefit from the experience of others 

 in either guarding against any injurious effects of this great pres- 

 sure upon the workmen and engineers subjected to it, or of avail- 

 ing myself of any known specific for relieving those affected 

 by it. 



When the depth of 60 feet had been attained, some few of the 

 workmen were affected by a muscular paralysis of the lower limbs. 

 This was rarely accompanied with pain, and usually passed off in 

 the course of a day or two. As the penetration of the pier pro- 

 gressed, the paralysis became more difficult to subdue. In some 

 cases the arms were involved, and in a few cases the sphincter 

 muscles and bowels. The patients also suffered much pain in the 

 joints when the symptoms were severe. An average of at least 

 9 out of 10 of those affected suffered no pain whatever, but soon 

 recovered, and generally returned to the work. 



The duration of the watches in the air-chamber was gradually 

 shortened from 4 hours to 3, and then 2, and finally to 1 hour. 



The use of galvanic bands or armor seemed, in the opinion 

 of the Superintendent of Construction, the foreman of the 

 chamber, and the men, to give remarkable immunity from these 

 attacks. They were all ultimately provided with them. These 

 bands were made of alternate scales of zinc and silver, and were 

 worn around the wrists, arms, ankles, and waist, and also under 

 the soles of the feet. Sufficient moisture and acidity were sup- 

 plied by the perspiration to establish galvanic action in the 

 armor, and, as the opinion of those most accustomed to the 

 chamber was almost unanimous in favor of this remedy, I am 

 very much inclined to believe it valuable. 



Immediately on the manifestation of greater severity in the 

 symptoms, a hospital-boat was fitted up at the pier, and one of 

 the ablest physicians in the city (Dr. A. Jaminet) was engaged to 

 attend those affected, and also to institute such sanitary measures 

 as his judgment should dictate. A careful examination of the 

 health and bodily condition of every workman was dail}' made, 

 and none were permitted to engage in the work without the ap- 



