CAISSON ILLNESS.
Thit suddenness of change from the much higher pressure of the atmo sphere in the diving-bell or caisson to that of the ordinary atmosphere is the cause of this condition, which is also known as Diver's Paralysis.
Before reaching the surface the diver is made to enter an intermediate chamber, or air-lock, where the pressure is gradually reduced, and when this decompression has been very carefully performed, and a sufficient time spent in the lock (15 minutes or more), usually no symptoms occur. When they do show themselves, which may be some hours afterwards, the paraplegia, and intense muscular and joint pains, vomiting, epistaxis, &c., can be relieved at once by replacing the patient in the lock and in creasing the pressure. This is known as the process of recompression followed by decompression.
A suitable air-chamber on the bank, in which the pressure can be dimin ished very slowly and accurately, and in which divers liable to suffer from Caisson illness may be kept for a few hours if necessary, prevents effectively all trouble and relieves distress when this has already appeared.
The pressure should be reduced at the rate of half a pound per minute in the act of decompression, after having been gradually raised to the ordinary working pressure and kept there for a few minutes.
Before entering the high pressure on first descending, the operative is submitted to a process of gradual compression in the lock, and in this other symptoms of the illness may appear; these. such as severe earache and giddiness, usually pass off when the diver is made to swallow air with the view of keeping open the Eustachian tube.
The severer symptoms on reaching the surface after passing through the air-lock before decompression has been thoroughly accomplished are usually seen in stout plethoric subjects, and Morphia hypodermically is often necessary owing to the agonising pain. Venesection may be re sorted to where unconsciousness supervenes. 'Where the paresis con tinues, rest with massage and electricity and the usual remedies indicated in chronic spinal myelitis must be employed.