For the rest I agree with Carl Rosenthal that by experiments with massage one finds that pressure generally rises with slowing of the pulse and falls when the beat is more frequent.

The innervation of blood vessels and facts pertaining thereto must not be lost sight of by those who wish to understand the effects of massage; its direct as well as its reflex effects must be considered.

It is scarcely necessary to remind my readers of vaso-constrictor and vaso-dilator nerves. We all remember Bernards celebrated experiment in 1851; section of the cervical sympathetic nerves of the dog produced hyperemia of the corresponding ear; and Brown Sequard's discovery in 1853 that stimulation of the peripheral stump caused the blood vessels to contract again. We may likewise recall how the discovery of the vasodilator nerves followed closely upon Bernard's experiment in 1850, in which by stimulation of the chorda tympani he produced dilatation of blood vessels and hyperemia of the submaxillary gland; also how Vulpian by his researches on the lingual and glosso-pharyngeal nerves, and Eckhard and Loven by their researches on the erector nerves, increased our knowledge of vaso-dilator nerves. Different investigators have since shown that both these varieties of nerves are widely spread in the body, often occurring in the same nerve trunk, stimulation of which under different conditions causes one or the other to take the upper hand, the constrictors generally predominating. Active hyperemia may therefore be caused either by paralysis of the vaso-constrictors or by stimulation of the vaso-dilators; hypearemia due to the latter cause always lasts little longer than the stimulation itself, while that due to paralysis of the constrictors may last a long time. On the other hand, a local anemia is not produced by paralysis of the dilators - their section produces no contraction; in other words, they have no tonicity.

This last fact is important and has made many physiologists consider vaso-dilators as "inhibitors" nerves. One can imagine that a muscle contraction produces as a reflex, via the muscle's centripetal nerves, an inhibition of the centre for its own vaso-constrictors, by which inhibition the vaso-constrictors lose their tone and the blood vessels in the muscle dilate.

Lastly, one must recall that the splanchnics are the most powerful vaso-constrictors, since they control the voluminous stream in the mesenteric blood vessels, the narrowing of which is of itself sufficient to produce increase of pressure in the heart and arteries, while their dilatation produces lowering of pressure; and that the splanchnics stand in a certain reciprocal relation to the other vaso-motor nerves, which are not, for the most part, capable by themselves of exercising marked influence on blood pressure.

The vaso-motor nerves go from the spinal cord by the anterior nerve roots between the brachial and lumbar plexuses, and by rami com-municantes to the sympathetic nervous system. (On the arrangement of this system see later in connection with the effect of active movements on the nerves.)

The peripheral nerve trunks therefore contain vaso-constrictor and vaso-dilator fibres. Short, gentle stimulation produces first contraction of the blood vessels with anaemia and pallor; but continued or strong stimulation, on the contrary, always produces dilatation with hyperemia and redness. This hyperaemia, which can be produced by other means better than by massage, helps reabsorption. I do not intend to discuss here how hyperemia promotes the absorption of chronic nonpurulent inflammatory products, but that it does so is an undoubted fact. To this end we also use hot mud-baths, water or sand baths, hot air or light baths, etc. To produce hyperemia which will promote absorption in pannus we cause an inflammation by the use of jequirity, and Bier has demonstrated that even the slight passive hyperemia produced by his bandage has the same effect.

The effect of massage on the blood pressure is very variable and depends on many factors. The lack of uniformity in the numerous experiments on this question has produced a dissimilarity in results and opinions which does not exist in regard to the other effects of massage.

Our most important knowledge on this subject, as well as what is most important for the masseur to remember, is that in most cases, by a reflex effect on the vaso-motor nerves, massage can produce contraction as well as dilatation of large areas of blood vessels, and rise as well as fall of arterial pressure. On the whole rise of pressure is more usual, more noticeable, and in practice more important than lowering of pressure. The rise of pressure, which may be very considerable, is a contra-indication to massage in all cases in which haemorrhage is likely. This contra-indication is most concerned with abdominal kneading, and is most important in cases of high degrees of arteriosclerosis and in gastric ulcer.

Effleurage has less effect on blood pressure (see p. 42). Petrissage and tapotement have a greater effect, while the result of vibration or shaking over the whole body is still greater. Abdominal massage has, as already stated, a very important influence, but its effect on blood pressure is variable.

Just as variable as the effect of massage on blood pressure, but in practice of far less importance, is the effect of massage on the frequency of the pulse. Stimulation of the vagus, with its always perceptible retardation of the pulse, occurs much less frequently than one might suppose.

Blood pressure depends on the mass of blood, on the systolic force of the heart, on the amount of blood sent into the vessels at each systole, on the elasticity and tension of the muscular walls of the vessels, on the peripheral resistance of the arterioles, and also on the viscosity of the blood.

The most important force in raising blood pressure is stimulation of the splanchnics and the consequent vaso-motor constriction of the voluminous mesenteric area, which is of vast importance in the regulation of blood pressure. Compression of the abdominal aorta, which is easily brought about by abdominal kneading, causes immediate rise of blood pressure centrally from the seat of compression. Among pathological conditions which require caution in raising blood pressure, arterio-sclerosis is the commonest and the most important.