From what has already been said we gather that fatigue (Physiology And Pathology Of Fatigue), that is, the inability to produce force, may be due to two causes: (1) a general dearth of albumens in the blood, and (2) a condition in the blood which leads to its defective circulation through the tissues, so that though the blood contains sufficient albumens the tissues cannot readily obtain them, and also the tissues become, as the result of their activity, laden with waste products, which are not sufficiently quickly removed.

It will be well to go somewhat deeper into this causation of fatigue (Physiology And Pathology Of Fatigue), so as to obtain the power of distinguishing in practical experience, between the fatigue which is due to the first, and that which is due to the second condition.

Now the fatigue (Physiology And Pathology Of Fatigue) which is due to dearth of albumens in the blood is always absent so long as sufficient food is taken and digested; in the condition of dyspepsia mentioned in the previous chapter it was not digested: so that, if a man in any trial of endurance drops out while supplied with sufficient albumens and apparently digesting them, we may be sure that his fatigue (Physiology And Pathology Of Fatigue) is not due to (1), but by exclusion is probably due to (2).

And practically, apart from digestive accidents, the fatigue (Physiology And Pathology Of Fatigue) which is due to dearth of albumens does not occur, till some four or five hours after a meal, and till urea has begun to fall very considerably below the level of 17 grains per hour, as shown in figs. 2 and 3 for instance.

So that, if a man, who has had a sufficient supply of albumens put in, and has a good digestion, yet falls out in the early stage of a contest, long before those albumens can be exhausted, we must conclude, that his fatigue (Physiology And Pathology Of Fatigue) is due to uric acid in the blood, and may proceed further to identify this condition by considering its concomitant signs and symptoms.

As will appear from my consideration of this subject in "Uric Acid" (prev. ref., p. 341), there is, in addition to the feeling of powerlessness in the limbs, a feeling of chilliness, with coldness of skin and extremities, and a fall of the surface temperature, but the temperature in the rectum will be raised and separated more than usually from the surface temperature (sign of excess of uric acid in the blood): similarly, and for the same reason the general blood pressure will be raised, the diameter of the radial artery increased, and the sounds of the heart altered. Under this condition, if a white spot is made by pressure with the finger-tip on the back of the hand, the colour will take from 2 to 3 seconds or more to return; while where there is no excess of uric acid in the blood, it may only take from 1 1/2 to 2 seconds.1

Now these are all effects of one and the same cause, defective capillary circulation, which can be seen on the back of the hand, affecting especially the temperature of surfaces and extremities, but affecting also the general circulation of the whole body, raising the blood pressure and influencing the action of the heart.

On the other hand, the man, who suffers from fatigue (Physiology And Pathology Of Fatigue) owing to deficiency of albumens, will not suffer from coldness nearly so much; will have but little difference between surface and deep temperatures, and little if any slowing of the capillary reflux on the back of the hand; will not have a general rise of blood pressure with increased diameter of the arteries, or much alteration of the sounds of the heart.

This man is all right in himself, but supplies have merely run short; give him fresh albumens, and a little time (as we see from fig. 1 is required) to digest them, and he will promptly be himself again; or even a little rest without any fresh albumens will enable him to draw on his reserves and tissue albumens, and he will be able to go on once more.

1 See British Medical Journal, Oct., 1899.

Far different is the case of the other man, for even if you supply him with albumens it will do but little good, he has already sufficient in his blood, but they cannot get to the tissues, and, owing to the general defective circulation, his digestion of any new albumens will be as slow as all his other physiological processes.

To supply him with fresh food may merely add to his troubles by starting dyspepsia, if not putrefaction, in his digestive organs, and presently he may vomit all the fresh supplies almost untouched by digestion.

To get this man once more into a condition to proceed may be a matter of hours, possibly days, and the first thing to do is to clear the uric acid out of the blood, and if this can be done, and as soon as it is done, there will be a rise of urea and a return of power without any fresh food having been given: this further illustrating the points already mentioned in reference to figs. 4 and 5.

Now the best way to clear the blood of uric acid is, as we see from the above figures, to give acids, acid wines, acid fruits, in fact acid in any form most likely to be absorbed from the stomach; or calomel, or other metals that form insoluble compounds with uric acid, as pointed out in previous writings; but as the whole object of this book is to show that, with proper care in selecting our sources of albumen, this fatigue (Physiology And Pathology Of Fatigue) from uric acid collaemia and the obstructed 3 circulation it produces need not occur, I shall not here go further into the treatment of the condition by means of acids and drugs.

But while speaking of this, I will again point out that, though the albuminous foods are those that really control the situation, other foods may have effects which may easily appear to others to be of more importance than they really are.

Thus, though in fig. 4 the effect of 1 oz. of sugar is very small compared with that of 1 oz. of cheese, any one who had taken the sugar would say that they felt distinctly stronger and better for it; and so they would be, while acidity and urea were rising, partly because some albumen was indirectly rendered available for force production, and partly because the amount of uric acid in the blood was diminished and the circulation improved.