Submarine Appliances And Their Uses
Deep Sea Diving, &c., &c.

NOTES ON THE SELECTION OF DIVERS AND CAISSON WORKERS. They should be steady men, of good physique, capable of sustaining a good bodily strain ; they should undergo a strict medical examination as follows :— The candidate should be of good physique and free from obesity. Particular attention is to be taken that he is free from any cardiac or pulmonary disease ; that he suffers from no active constitutional complaint, such as syphilis, albu- minuria, etc., and .shows no sign of middle ear disease ; that there is no history of fits of any kind, and that he is not addicted to alcohol or smoking in excess. There should be no tendency to varicose veins or arterial degeneration. Periodical Examination of Divers.—Every man before diving should be carefully examined as to the above conditions. He should not go down directly after a heavy meal, and his general health should be good. His bowels should be kept regular. For deep diving, or work involving very long stays on the bottom at more than io fathoms (6oft.), men beyond the age of forty-five ought not to be employed. Very Fat Men Not Suitable for Deep Diving. Dr. A. E. Boycott, M.D., and Lieutenant G. C. C. Damant, R.N., have carried out experiments on the influence of fatness on susceptibility to caisson disease. Their conclusions are summarised as follows:—■ “The practical conclusions are clear. Really fat men should never be allowed to work in compressed air, and plump men should be excluded from high- pressure caissons {e.g., over + 25 lb.) or in diving- to more than about 10 fathoms, and at this depth the time of their exposure should be curtailed. If deep diving is to be undertaken, or caissons worked at pressures approximating to + 451b., skinny men should be selected. It is unfortunate that an increase of experience and skill in tech- nical operations should so often be associated with the increase in waist measurement which accompanies the onset of middle life. Middle-aged men have a lower rate of respiratory exchange than young- men ; if fatness is not the explanation of this, they are at a double disadvantage, and the two factors must be multiplied, rather than added together.”—{Journal of Hygiene, Vol. VIII., No. 4, September, 1908.) 21