out the exercise of much imagination, be considered as storehouses, in a subsidiary sense, of the outflowing energy, and as capable of playing a part in the automatic contractions evinced by that organ, when separated from its grosser nervous connections.

Among rhythmically contracting organs we must also include the arteries and some veins; and the extra-neural situation of ganglia on nerve trunks regulating the vascular supply of such an excretory organ as the kidney, seems likewise to suggest that a subsidiary storage of energy in these nerve-producing cells is not incompatible with the trophic power more generally conceded to them.

To return to the analogy between secretory and viscero-motor innervation, it will be remembered that I described two kinds of ganglia in connection with the heart, namely, those on the trunks of efferent nerves, and those which lie in the intervascular fat at the base of the heart and under the epicardium, it may be close to such efferent trunks, but apparently unconnected with them. They also occasionally lie, as has been stated, in close relation to blood vessels. The latter kind appear to be the distal ganglia of the sympathetic system, and probably differ in function, as they do in anatomical character, from the ganglia of the vagal stream.

The deeper relations of these varieties of ganglia to one another are not easy to determine, but it is as improbable that they should lose their individuality, as it is unlikely that the fibres of their respective nerves should anastomose at the periphery. They doubtless each supply nerves which have a common destination, namely, the muscle cells of the heart, and of the vascular system pervading it.

In explanation of the varying rate of the heart's action, I was at one time disposed to believe with Schmiedeberg (quoted by Brunton),1 on purely hypothetical grounds, that the ganglion cell was a mid-point between the nerves slowing and those quickening the heart's action, and that this cell played in some measure the part of regulator. I now consider it more probable that the term common to the two streams of innervation, which both contain sensory and motor elements, is the muscle cell itself, and that the stimulus which calls the one or the other system into predominant activity is physico-chemical in nature, and due to cross stimulation of the two sets of nerves. By cross stimulation I mean the stimulation of one set of nerves by the products of the activity of the other. The chemical stimuli, if chemical they be, 1 66 'Pharmacology, Therapeutics, and Materia Medica," London, 1893.

would, I presume, be termed by Gaskell anabolic or katabolic according as they were the result of retardation or of acceleration of muscular action.

The cross action is probably reflex in character, the anabolic products of retardation stimulating the accelerant sensory nerves, while the katabolic products of acceleration excite the afferent sensory fibres of the vagus.

I am aware that these remarks are based upon anatomical facts and clinical interpretation, rather than upon physiological observation, the result of experiment.

I have no desire to dogmatise on so obscure a theme, and remember, in a chastened mood, the numerous instances in which an apparent finality in scientific opinion has proved but the point at which a reversal of preconceived notions has taken place. For this reason also, as a humble opponent of the rampant Hallerism of the hour, I await with some curiosity, not unmixed with a measure of confidence, some modification in the views of anatomists and physiologists as regards the nerve supply and functions of the "ganglion free apex," which at present bulks so largely in the discussion of rhythmical muscular action.

Yielding all over the body to the perpetual encroachments of its predominant partner, the cerebro-spinal nervous system, the last refuge of the sympathetic vainly struggling to be free, was what has come to be known as the hypogastric reflex. This may be observed when the inferior mesenteric ganglion is separated from all its connections with the spinal cord, and when, in addition, one of the hypogastric nerves issuing from it to supply the bladder is divided. Stimulation of the central end of the latter by electricity is observed in some cases to be followed by muscular contraction of the bladder.

To account for such a phenomenon, on the assumed residual integrity of some portion of the connections of the ganglion with the cord, does not appear to be quite necessary. Electricity will be conducted by a continuity of conductive material in various directions; and the simplest explanation seems to me to be, the mechanical stimulation of structures storing and conveying efferent energy, that is, of the ganglionic cells and their centrifugal fibres in the ganglion in question.

Before leaving the subject of the efferent passage of energy into the viscera, I desire to make a few remarks upon the question, as to whether there is any reason to suppose that the

piace

progress of the efferent current is influenced by the anatomical character of the chain it traverses. If Kölliker be correct in his belief, that the visceral afferent fibres reach the centre, without arborising on intervening ganglion cells, except in so far as they arise from the cells of the ganglion on the posterior root, while it is admitted that the whole efferent stream of visceral innervation undergoes the interruption or complication of cellular arborisation before ultimate distribution, it might, a priori, be supposed that such an anatomical difference implied some distinction, other than the broad one known to exist between these currents, namely, the sensory nature of the one and the motor nature of the other.

As regards the sensibility of the viscera, the experience of the physiologist, of the surgeon, and of the physician alike, serve to show that its conditions are peculiar.

As Foster states 1:

In respect to all structures other than

NB. the skin and nerves to such structures, namely, as muscles,

tendons, ligaments, bones, and viscera generally—there is a large amount of experimental and clinical evidence, showing that, so long as these are in a normal condition, experimental stimulation does not give rise to any distinct change of consciousness; a muscle or tendon, the intestine, the liver, or the heart, may be handled, pinched, cut or cauterised, without any pain or indeed any sensation at all being felt, or any sign of consciousness given. Nevertheless, when the parts are in an abnormal condition, even slight stimulation may produce a very marked effect in consciousness."

When we arrive at the clinical portion of these lectures, this question will meet us again. My object in referring to these points at present is, to emphasise the fact that our perception of pain, arising from visceral causes, may be as acute as any capable of being generated elsewhere, and that the nature of sensibility, except in the skin, does not differ appreciably in the somatic and splanchnic divisions of the nervous systems.

On the other hand, be the condition of the viscera what it may, our voluntary control over the efferent stream of innervation flowing towards them is equally small. The channel to our perceptions, in other words, from the viscera to the brain, is potentially quite open; the channel for our will is, somehow, blocked between the brain and the viscera.

The emotions, however, affect the viscera as easily as they do

1 Op. cit., p. 1420.

the parts supplied by the somatic nerves. The difference, one is tempted to say, between the emotions or feelings and the will is the difference between the afferent and efferent sections of the nervous system, the emotions, or "feelings," being sensory, the volitions sensori-motor. It is more correct, however, to say that the stations for emotional reflex stop short of the nervous centres of will.

The genius loci urges one at this point to make a digression into metaphysics in the city of Dugald Stewart, of Thomas Brown, and of Sir William Hamilton. But we must remember the pitying smile with which the conventional physiologist would regard us, did we do so in the course of a physiological lecture, and leave to a more convenient season that wrestling with the transcendental for which our countrymen are famous the world over, and which has contributed in no small measure to their success in more material spheres. For your transcendentalist can, on occasion, be an exceedingly practical person, as the Afghan discovered who was charged by Rudyard Kipling's Highlander, after the latter had philosophically commented upon the unfortunate necessity involved in the occasional use of the bayonet! The difference between the power of emotion and of will to affect the viscera is nevertheless worthy of won

comment.

The emotion which arrests the heart's action or checks digestion appears to be a descending inhibition, liberating, on the theory advanced, products which, under normal conditions of the muscle and secretory cell, provide sooner or later a cross stimulation of the complementary sympathetic visceral nerves, and hurry the heart into katabolic activity. Whether this holds good also in the case of the gastric and other secretions, and a complementary sympathetic juice comes to the aid of the inhibited vagal secretion, we cannot, so far as I know, positively assert at present. But such experimental evidence as we possess does not appear to contradict such a notion. On the principle, moreover, of compromise, adaptation, equipoise, or, as Herbert Spencer terms it, "equilibration" in nature, which pervades and knits the everchanging but indestructible whole, such a process would seem very reasonable.

On the other hand, notwithstanding the oft-quoted case of "the Honourable Colonel Townshend," who is stated to have 1 Cheyne's English malady, quoted by Guy and Ferrier ("Forensic Medicine," p. 239).

been able to arrest his heart's action at will, no effect upon the viscera, brought about by volition, is in any way comparable to that constantly exercised by the emotions upon these organs. None such is conceivable or known.

The rehabilitation of the scientific reputation of ancient worthies in the sphere of splanchnic physiology is a noteworthy phenomenon. Haller has many supporters of his theory of nerveless rhythmicality in the present day. Remak's accuracy has been vindicated by Paterson in his embryological study of the sympathetic system. I also venture to recall the name of an almost forgotten physician, whose views appear to me to contain an element of truth, which has not been altogether discredited by subsequent research.

Dr. James Johnstone, in his "Essay on the Ganglions of Nerves," published at Shrewsbury in 1771, maintained some theses which cannot be supported with our present knowledge of the subject. But in regarding ganglia as "checks to the process of volition" (p. 22), and if we restrict our meaning to ganglia of the efferent stream, it appears to me that these structures, in their histological condition and physiological behaviour, support Dr. Johnstone's opinion.1

Did the efferent stream pass through the peripheral ganglia, without arborising on nerve-producing cells, as Kölliker considers the afferent stream does, it is highly probable that our voluntary control of the viscera, if spasmodic, would in any case be as

1 James Johnstone was born in 1730, at Annan in Dumfriesshire. It was inevitable, therefore, that one or other of his descendants should unsuccessfully claim the dormant Marquisate of Annandale. This one of them did some years ago. Johnstone studied under Whytt, whose portrait hangs on these walls, and graduated as doctor of medicine at the University of Edinburgh in 1750. He is not to be confused with his son James, who also graduated in Edinburgh in 1773. Johnstone, after studying in Paris, settled in practice at Kidderminster, and later

at Worcester, where he died in 1802. His first essay on "The Use of the Ganglions of Nerves" was published at Shrewsbury in 1771, and in 1795 again formed the most important part of his "Medical Essays and Observations." His employment as a disinfectant in typhus, of "the thick white steam of muriatic acid, set free by pouring small quantities of vitriol from time to time upon common salt, heated in a chafing-dish of coals," was recommended for use by a committee of the House of Commons in 1802. These facts, together with his publication of an essay containing a scheme for the abolition of slavery, show him to have been a many-sided and ingenious man. Further particulars concerning him are to be found in the "Dictionary of National Biography," from which some of the facts mentioned were gathered.

As I have stated, there is no question of the adoption of his views concerning the functions of ganglia, as a whole, but his essay contains suggestions well worthy of consideration even in the present day.

Will