present allowance in England is 600 cubic feet of space to each man in barracks.

The ills of sailors are, to a very great extent, caused by want of fresh air, dirt, and dampness. It is commonly forgotten that, by washing down the deck frequently, a source of disease is introduced which is at least as dangerous, and in feverish localities ten times more dangerous than simple dry dirt. Good ventilation and scrubbing and drying are the cure for the chief of the curable ills of ship-life.

CHAPTER III.

INJURIES FROM OVER-USE OF CERTAIN ORGANS.

T is as true of the mind as it is of the body, that no one part can be exclusively used without injury to the individual considered as a whole. In the broadest possible division of our being, neither "mind" nor "body" has a right to exclusive cultivation; and such exercise is never in the interest of the best physical health. The same is true if we subdivide the faculties of body and mind. There are many ways in which the mind is exercised in daily life: bookstudy, concentration of attention on discourse, memorizing, reproducing, extemporary discourse; attention to great single questions in business, and to multitudes of petty ones; ciphering and copying by the day, and the vivid, sudden, mortal collisions of the street. None of these can properly be kept up to the exclusion of the others, unless there is a strong predisposition and fitness on the part of the individual : they should alternate with one another, for most persons are incapable of sustaining continued strain in one of these points. We say that "worry" kills a man;

but in saying so we mean simply that the mental excitement upon one subject, which is perfectly healthful if continued for a few hours, becomes tyrannical and destructive if kept up for whole days. A man may be worried into illness by incessant, quiet ciphering as well as by attendance at the Brokers' Board.

The care of the mental health has been sufficiently treated of in another of this series of Primers.* It is my purpose here briefly to mention some muscular affections which are caused by monotonous and excessive work.

The robust activity of the blacksmith and carpenter do not exempt them from the general law. They are liable to a disease termed " 'hammer-palsy," affecting the muscles which are overworked.

A painful and very unfortunate affection sometimes attacks those who write a good deal. The premonition is given sometimes by pain in the muscles employed in holding the pen. There is apt to be a nervous condition of the system, a tendency to anxiety; but this is not always the case. As seen in its typical form, the disease presents no token of its existence until the person affected begins to perform one special act, as, in the present instance, the act of writing. There may be great muscular vigor, and complete control of all the faculties and motions

*" Brain-Work and Overwork," by H. C. Wood, M.D.

except one; but as soon as the patient undertakes to grasp the pen and write, he finds his fingers in a state of cramp; they pinch the pen excessively, or they fly back from the pen, making it impossible to hold it. It is very desirable that this should be recognized in an early stage, as it is a malady somewhat difficult of cure, and absolutely disabling as respects clerical work. Some reader may thank me for saying that electricity has been applied of late with good success to the treatment of Writer's Cramp or Palsy.

The affection here described is not confined, however, to writers, but affects also pianists, violinists, engravers, seamstresses, telegraph-operators, tailors, type-setters, and many other classes who use one set of muscles almost exclusively.

The theory has been put forward that writer's cramp is caused by an electric current generated in a metallic pen, or by the contact of pen and holder. This cannot be admitted. The disease is fundamentally the same, whether caused by work with the pen or on catgut or ivory. But a steel-pen may be found injurious, and can be replaced by gold or quill; or a large pen-holder may be used, made of cork, of the size and shape of a large cigar, which is felt by many to be a great comfort in writing. A departure from the prescribed mode of holding the pen, and placing it between the forefinger and the middle finger, may also be a relief. Dr. Frank Woodbury, of Philadel

phia, has lately invented an ingenious pen-holder to prevent writer's cramp, by regulating the pressure at which the pen is used by a slight spring. But if the disease has developed itself, no such palliation is of any avail; and if the sufferer learns to write with the left hand, as has been done, the left hand also is liable to be attacked. The temporary use of the "typewriting machine" will often prove a great boon, permitting a continuation of work while resting the affected muscles.

The effect of using sewing-machines is sometimes injurious. It is not worth while to mention any special effects. The muscular exertion, however, is of a monotonous character, and may produce muscular fatigue which is prejudicial to the general health. It has been known to cause neuralgia of the foot and leg. In general, the use of the machine two or three hours a day is probably beneficial to most women; but a whole day's work, if the machine is run by the feet of the worker, is far too severe, and steam-power had better be used. Much has also been done by applying the principle of alternate effort, by a treadle which is moved both by the downward and the upward movement of the feet, and employs both feet at once or one at a time, at will. Many will find relief by alternate basting and sewing each for twenty to thirty minutes.

Steam-power has been applied with success to run