In the preceding chapters we have seen that medical gymnastics and massage have a great effect on local and general nutrition. We know that effleurage has an important effect on the local circulation in cases of atrophy, it prevents gangrene (in frostbite, etc.), and is of great value as an aid to healing; that tapotement in its various forms is useful in cases of disturbed nutrition of muscles and nerves; that abdominal massage, by improving absorption and peristalsis, is an indirect aid to nutrition. We have seen, further, that general massage has a similar effect by increasing the number of blood corpuscles. Gymnastics greatly influences metabolism; it increases the nitrogen in the urine and promotes the combustion of fats and carbohydrates to carbon dioxide and water. Massage, especially muscle massage, has the same influence to some extent, but in a much less degree.

The main therapeutic and hygienic value of gymnastics lies in its marked influence on circulation, respiration, and assimilation.

On these points our knowledge is very crude, and we are unfortunately ignorant as to the more intimate processes of nutrition. In illustration of our ignorance the reader is reminded how little is really known of intracellular life and of the mystery of trophic nerves, both of which remain a problem confronting us at every stage of investigation, when we attempt to trace the aetiology of those allied dystrophies, obesity, gout, and diabetes.

In comparison with the gaps in our knowledge it is relatively of slight importance that we have not mastered the problem of the expenditure of energy, i.e., heat and movement in work. Generally it is assumed that of the expenditure of energy stated in terms of calories expended, two-thirds is converted into heat and at most one-third into work. According to Zuntz these figures are a maximum; Helmholz and others assume that only one-fifth of the calories used is expended by the human body in movement. I may repeat that for all patients with general disturbances of nutrition who are able to walk, gymnastics are best carried out by the terrain-cure, in which we cannot give detailed directions as to movements beyond the choice of slope. Meanwhile we may remember that expenditure in concentric movement is more costly than in eccentric, since a greater part of the expenditure of energy is transformed into work in the former than in the latter. Movements involving ascent are largely concentric; conversely those involving descent are largely eccentric.

The reader is referred to what has already been said of Stokes' cure in the treatment of heart and lungs, since most of what has been said there refers equally to cases of obesity, gout, and diabetes. In these last cases, however, walking on an incline is of less importance than it is for affections of the heart and lungs, and any walks may be taken provided they are of adequate length.

Massage also plays an important role. General massage is then used with modifications to suit the particular case treated.

The importance of diet justifies a short section to itself.