When a cannula is placed in the carotid of a dog or rabbit and connected with a manometer a definite rise of blood pressure is seen during abdominal kneading, chiefly due to direct and reflex stimulation of the splanchnics and consequent narrowing of the mesenteric blood stream; if the manipulations are performed strongly over the abdominal aorta, compression of the aorta acts in the same way. In these cases I never continued abdominal massage for long; several reliable observations have shown that if this is done the rise of pressure is followed by a fall. By means of sphygmographic tracings of the radial pulse in man during abdominal kneading I have seen a definite rise in the height of the pulse wave, and after five minutes' massage this effect could still be observed for an hour. During abdominal kneading the pulse sometimes becomes definitely dicrotic, tri- or tetra-crotic. One would expect by analogy from Gott's experiments on the heart-beat, and from what is often the case with rabbits, to find a slowing of the heart-beat during abdominal kneading. But in man, in the few experiments I have undertaken on this point, I have repeatedly found a definite quickening of the pulse. After half an hour's energetic abdominal massage the pulse-rate is often practically unchanged; what is most remarkable about it is that a pulse which at the beginning of the treatment was weak or almost imperceptible became quite strong. The frequency of respiration, at least in many cases, is increased.

The results of more recent experiments are as folows : - By massage of the lower extremities Eccles found the pulse-rate diminished and blood pressure increased. He found blood pressure first increased but later diminished by abdominal massage.

Edgecombe found the pressure raised by abdominal massage.

Cautru found it lowered.

Le Marinel, Lauder Brunton, and Tunnicliffc found blood pressure increased by abdominal massage in dogs and cats. The two former writers observed it fall after the treatment.

Von Bechterew and Tschigajew found shakings of the whole body constantly produce a definite rise of blood pressure in man; the temperature at the same time fell in the axilla and rose in the rectum. Hase-brock also found increased blood pressure and diminished pulse-rate.

Romano found that abdominal massage in dogs and cats raised blood pressure and diminished the pulse-rate.

Ekgren found the blood pressure lowered by this form of massage.

Rosenthal says that general massage commonly produces a rise of blood pressure = 25 to 30 mm. Hg.

Zabludowski, Kronecker, and Stirling found that all massage in the form of eflleurage, friction, and petrissage increased the pulse-rate; the two last mentioned found that tapotement diminished it.

Hasebroek, Romano, Eccles, and Ekgren found the pulse-rate generally diminished.

E. Weber states that long-continued peripheral mechanical stimulation produces first dilatation, later contraction, of the cerebral blood vessels.

F. Pick showed that during effleurage over the lower extremities the blood stream was quickened in the femoral and mesenteric veins, and slowed in the jugular. In long-continued abdominal massage the blood stream in the mesenteric vessels became wider and quicker, but narrower and slower in the cerebral vessels.

Colombo performed extensive and valuable experiments on man. He found that gentle effleurage over a large area somewhat raised blood pressure; effleurage over all four extremities simultaneously raised it as much as 20 mm. Hg.; vibrations raised it more, especially when done on the skin. Strong eflleurage and vibrations raised the blood pressure and diminished the pulse-rate. Gentle tapotement produced a slight rise of pressure, harder tapotement a more marked rise. Muscle massage often produced a marked rise of blood pressure up to 50 mm. Hg. General massage usually raised blood pressure as much as 30 mm. Hg. Gentle abdominal massage produced rise of pressure with diminished pulse-rate; strong and long-continued abdominal massage lowered pressure (by 10 mm.) and increased the pulse-rate.

Metabolism is influenced by every form of massage performed over large areas of the body.

It is necessary, however, here to define the limits of what I mean by metabolism; a disastrous confusion reigns in regard to this term. By metabolism I mean all those molecular changes which take place within the organism in those elements which form the normal constituents of tissues. From the term metabolism I distinguish every process of digestion by means of which food in the alimentary canal is prepared for absorption by its mucous membranes, and the absorption which takes place. There is some proof that abdominal kneading has a definite influence on digestion and absorption.

One may summarise what can be said of the influence of massage on metabolism in the tissues as follows : - Muscle massage in the form of effleurage, and still more in the form of petrissage and tapotement, is that part of general massage which (probably mostly by local muscle contractions) chiefly affects metabolism; this influence is shared in some degree by every form of massage performed over a large area for any considerable time. Massage involving increased activity of the digestive system causes increased nitrogenous secretion. Diuresis is increased by the increased blood pressure, and the increase in the blood of substances which irritate the kidneys.

Carbohydrate, and most probably fat also, is oxidised in greater quantities into C02 and water, and the total quantity of C02 expired is increased. Massage, however, has far less influence on metabolism than has gymnastics.

Zabludowski (1883) began a series of experiments by daily general massage, and observations before and after massage. Two of three individuals massaged lost weight and one gained. The last mentioned excreted less nitrogen compounds but more sulphates in the urine during massage than before or after; in the two first-mentioned cases both the nitrogenous matter and sulphates in the urine were increased. The only importance of these experiments is a stimulus to further inquiry, and one can draw no conclusion from them.

Gopadse (1885) carried out four more careful experiments, each for three weeks, and embracing all the nitrogenous intake and output. He found in all four cases increase of appetite, increased power of assimilation, and increased nitrogen in the urine, i.e., increased nitrogenous metabolism. One maintained, two increased, and one lost weight during massage. Gopadse's results are not quite convincing, since the increase of nitrogen in the urine was so slight (1 to 4 per cent.) that it might be connected with the improved absorption of food due to abdominal massage.

Weir-Mitchell is of opinion, although not quite certain from his experiments, that general massage produces a temporary increase of metabolism during the seance and noticeable for about three hours afterwards in the urine, but followed by a fall, so that the total metabolism during twenty-four hours was not considerably altered.

Keller (1889) found that general massage increased excretion of nitrogen, chlorides, sulphuric acid, and salts in the urine.

Polubinski (1889) performed various experiments on this subject the results of which are negative, but he will probably be able to come to a more definite conclusion at some future date. Kijanowski had the same misfortune. Bum (1893) did not trouble to control the diet of his patients, and we cannot therefore draw any conclusion from his experiments.

In Bendix's careful experiments of 1894 massage was found to produce a constant increase both of the quantity of the urine and of nitrogen in the urine. This increase sometimes only began after several days' massage, but continued several days after the treatment ended. Otto Voigt (1896) obtained the same results, and he also found an increase of phosphoric acid in the urine. C. Rosenthal confirmed these results in 1908.

Finkler and Brockhaus, though their calculations were exaggerated and faulty, found that general massage of diabetic patients increased the power of oxidising sugar in the blood, i.e., decreased the sugar in the urine (see later on Diabetes Mellitus).

About 18901 stated that abdominal massage increases the secretion of urine.

Before that Zabludowski and Hirschberg had said that increased secretion of urine was produced by general massage, and the same results were arrived at by Polubinski, Bum, Le Marinel, Bendix, Voigt, and others. Bum showed that a somewhat extensive local massage may have a diuretic effect, by means of his experiments on the hind legs of a dog under curare, which showed a markedly increased secretion of urine.

Muscle massage and abdominal kneading increase oxidation and the expiration of C02 (Leber and Stuve, 1896), the increase rising to about 12 per cent. Hasebroek showed a diminished production of C02 by shaking and other forms of tapotement!

Wharton-Sinclair (in Weir-Mitchell's " Fat and Blood ") says that general massage increases the temperature of the body. Eccles (1885 - 1887) found that massage of the trunk and extremities increases the skin temperature but lowers it in the rectum, while abdominal massage has an opposite effect both on the skin and rectum. G. Berne (1886) also found a rise of skin temperature.

Von Bechterew and Tschigajew (1895) found shaking over the whole body lower the skin temperature but cause it to rise in the rectum.

General massage also has a very favourable effect on sleep, as on the general and psychic conditions.

Summary

We may thus shortly summarise this chapter : - All manipulations have to a certain extent the same effect, but each of them has a special effect. Effleurage especially helps the circulation in the blood and lymph vessels in and around the area over which it is performed, so that it raises local nutrition of the tissues, helps the healing process, counteracts atrophy or inflammation, and is a means of promoting absorption; it also has a restorative effect after fatigue. Friction more than any other manipulation promotes retrogressive changes and absorption of inflammatory products. Petrissage is a manipulation which also produces the same effect to a marked degree, but is also a powerful means of stimulating muscle. Tapotement, however, of all massage manipulations, is the most powerful means of stimulating muscles, nerves, and other forms of cells, especially gland cells. Tapotemcnt causes local muscle contraction, even when electricity and will power are no longer able to produce muscle action. Vibration over the head affects the nerve centres; this is demonstrated by its marked effect in producing sleep in patients suffering from insomnia. Vibration on other parts of the neurons, either by direct or reflex action, produces sensory (less often motor), secretory, and vaso-motor effects of different kinds; especially does it affect the force and frequency of the heart-beat and blood pressure. Abdominal kneading is of the greatest use as a means of treating atony of the stomach and intestines and laxity of the muscular coat of the alimentary canal; it affects the glandular secretions of the alimentary canal, appetite, digestion, and absorption; it has, moreover, a powerful influence on blood pressure and the pulse, an influence, however, which varies under varying conditions. General massage comprises the above-mentioned effects of effleurage, petrissage, tapotement, and abdominal kneading : it increases the number of red and white corpuscles; it has a variable effect on the heart and pulse, but generally it aids circulation, increases metabolism, increases the quantity of urine, the nitrogen in the urine, the salts and the quantity of C02 expired; but in all these effects on metabolism massage is much less effective than gymnastics.