we shall never find deposits of urates, and we might conclude that exercise never caused their production, though they would show themselves very abundantly in the urine of the third or fourth hour, which we have not examined.

But we can draw another conclusion from our observations namely that the organic substances forming these precipitates are slowly eliminated, and stay long in the economy before passing through the renal filter. Now we know that the kidney does not elaborate the substances which are found in the urine, but that it eliminates them as they are brought to it by the blood. The excrementitious materials, which are the waste products of muscular work, are then ready formed in the system before passing through the excretory organ. They can make their injurious influence felt for a long time, for they stay several hours in the economy.

We must add that this production of deposits of urates which begins three hours after the work, continues sometimes for twenty-four hours, that is as long as the general disorders of fatigue.

The time when the precipitate is observed being thus established, it is easy to study the influences on its production, firstly of the conditions under which the work is done, and secondly of the physiological condition of the worker.

If the work is not very severe and of short duration there will be no precipitate. The precipitate is very abundant on the other hand when the exercise is very violent and very prolonged. In the same individual the urinary deposits are more abundant, and appear during a longer period, the more intense and more sustained the muscular work necessitated by the exercise. According to the greater or less violence of the exercise, the precipitate will vary from a faint cloud in only one of the specimens, to the thickest deposits rendering turbid and muddy all the urine passed during twenty-four hours.

But the condition of the individual has much more influence than the severity of the exercise in increasing

or diminishing the quantity of deposit formed after the work. The nearer he approaches to the condition of training, the less abundant the deposits in the urine, the amount of work remaining the same. In proportion as from practice he acquires more power of resisting fatigue, his urine loses the tendency to deposit urates.

There is nothing more interesting than to follow the inverse progression of these two phenomena: power of resisting fatigue, and the formation of urinary deposits. If the same individual does every day the same exercise, demanding the same expenditure of force; if he undertakes for instance, to row a certain distance in an hour every day, his exercise, which causes great stiffness during the first few days, hardly produces any disturbance after a week's practice. His urine which at first gave abundant deposits, shows later only a faint cloud.

As the deposit becomes smaller, the sensation of consecutive fatigue tends to diminish, and when the urine keeps perfectly clear after the exercise, he will suffer from no kind of discomfort: there will be no stiffness. There is then a close relation, an invariable coincidence between the formation of deposits of urates and the production of stiffness.

This remarkable correlation is found in all circumstances which can alter the effects of work. If we pass from an exercise with which we are familiar, to another exercise calling into action a different muscular group, we experience afresh the discomfort of stiffness, and our urine again shows a deposit. Thus, a man used to forced marches, experiences no consecutive fatigue on the day following a long journey made on foot. He will, however, suffer from stiffness, if, without being used to it, he spends a short time in fencing. If we examine his urine, we shall discover that though it remained perfectly clear after twelve hours' walking, it is very turbid after twenty minutes' fencing. This will always be the result when we undertake a new kind of work, which brings into play muscles not hitherto exercised.

The close correlation between stiffness of fatigue and

the formation of excrementitious products which make the urine turbid, may be ascertained even in accidental circumstances which make the resistance of the individual variable, and render him for a time more vulnerable to fatigue. Under the influence of slight indisposition, of an insignificant disturbance of health, it often happens, as all amateurs of sport know, that the aptitude for work is for the time diminished. On these days the gymnast has not his accustomed vigour, and the exercise is followed by a long-forgotten sensation of discomfort. A man well broken in to his work shows, under these circumstances, the same phenomena of fatigue as a novice, and his urine, which for a long time has always remained clear after exercise, begins again to deposit

urates.

We have many times observed these facts on ourselves, and have been able also to record them on other persons, as the following observation shows.

A friend of ours, a good oarsman, in perfect training, offered himself for our studies on the changes in the urine produced by work; but he was so inured to muscular exercise that we could never find the slightest deposit in his urine. One morning we were rowing with him in the same boat, and we were surprised to see that he was wanting in his accustomed vigour; he needed all his force of will to go on rowing to the end of his ordinary course. Two nights without sleep had brought about this temporary enfeeblement. On this occasion the exercise left him throughout the entire day with a sensation of discomfort and stiffness, such as he had never experienced, and his urine, which for a long time had been very clear after work, showed very abundant deposits of urates.

Whenever the organism is in a condition of "diminished resistance," there is a tendency to the formation of deposits of urates, and a tendency also to a manifestation of the symptoms of stiffness.

It may happen that the deficient resistance of the organism is produced by a cause of the moral order, by

mental abstraction, by depressing emotion. We have been able to ascertain that, in this condition of physical and moral depression, a well-trained man loses for a time his immunity from fatigue, and shows, after muscular exercise, all the symptoms of stiffness; but, at the same time, his urine is not clear as usual after work, but deposits urates. We have observed this phenomenon in a man who was a great fencer, inured to all forms of exercise. He fenced every day, with no symptoms of stiffness, and no deposit in his urine. One day, after a short fencing bout, when his mind was preoccupied with thoughts of a serious duel he had to fight on the following day, he suffered from a very severe attack of stiffness, and we found an abundant precipitate in his urine.

Such are the facts of experiment and observation showing the constant correlation between the formation of deposits of urates and the production of the stiffness of fatigue. Every circumstance which makes a man more vulnerable to fatigue, causes at the same time a tendency to the formation of deposits in his urine.

Between these two phenomena, excretion of turbid urine, and discomfort following exercise, there is so constant a correlation, that it is impossible not to see in them a relation of cause and effect.

CHAPTER VI.

STIFFNESS (continued).

Objection to Our Theory-Are Urinary Deposits due to the Perspiration produced by Exercise?-Observations opposed to the opinion of Authors on this Subject-An Experiment in Fatigue-Rowing from Limoges to Paimbeuf-Agreement of Observations with Chemical Analysis-Exercise produces a Uricemic condition-Analogy of Stiffness of Fatigue with certain Febrile conditions-Stiffness of Fatigue and an Attack of Gout-Cause of Immunity from Stiffness when in Training— Function of Reserve Materials-Products of Dissimilation-Part played by Uric Acid in Stiffness-Stiffness is an AutoIntoxication.

I.

AN objection first presents itself against the conclusion we have just formulated.

Some authors consider urine which forms deposits after muscular exercise not as a liquid containing more excrementitious materials than in the ordinary condition, but as a more concentrated liquid, that is to say, one containing less water for the same quantity of solids in solution. Urinary deposits are not more abundant in urine after exercise, but the water which holds them in solution is less. Hence more saturation of the liquid and tendency to precipitation.* If the theory of these authors were true, these urinary deposits would not indicate any change in the chemical composition of the liquid; they would merely mean that a part of the water ordinarily eliminated by the kidney has been discharged by other channels, and notably by the skin. Excessive

* Dictionnaire de médicine et de chirurgie pratique. Art. "Urine."