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not succeed in doing so beyond the point reached by Retzius. A ganglionic cluster, with fine retiform ramification of fibrils, is shown in the preparation (Fig. 4). That the blackened cluster is ganglionic, is argued from a somewhat similar appearance, presented by indubitably ganglionic material, shown in a preparation of my own on the wall of a blood vessel supplying one of the cervical sympathetic ganglia in a child.

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The nerves in the case of the kidney, as in other organs, follow the course of the blood vessels. This relation of visceral

nerves to blood vessels

is well shown by the FIG. 5.-Relation of large nerves (a, a) to vessel (b)

preparations are figured.

which

from the pancreas of a mouse.

FIG. 6.-Mesentery of kitten. (a) Trunk of nerve; (b) branch going to supply the vessel (c).

The control of the blood-flow in a viscus is no less the note of empire in an organ than is the control of the waterways of our planet the ensign of sovereignty among nations (Figs. 5 and 6).

While we have thus failed hitherto, so far as I know, in demonstrating the complete innervation. of the glomerular capsule and its connections, there can be little doubt that the nerves are there for

[graphic]

staining, and with improvements in method will, sooner or later, be stained.

It is perhaps allowable to make a guarded inference from the innervation of the somewhat homologous Malpighian body in the

spleen. I am fortunate enough to be able to show a good Golgi specimen of the ultimate innervation of the spleen, for which I am indebted to Herr Hofmann. It will be observed that nerve fibrils reach and surround the Malpighian body, even anastomosing over it in the manner in which precellular cerebro-spinal fibrils touch and embrace the ganglionic cells of the sympathetic system. On careful examination, it will be seen that the vascular fallacy may be excluded in this case, as a Malpighian twig may be observed to arise from an unquestionable nerve fibril (Fig. 7). That these bodies, differing in function with the organ in which they occur, may

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(a) Nerve

FIG. 7.-Golgi preparation of nerves in the spleen of a calf. fibre; (b) Malpighian corpuscle; (c) connecting fibril; (d) nerve fibres and fibrils, some of which have gangliform enlargements.

be regarded as probably endowed with nerves in a similar manner, is, I think, a legitimate inference from the ascertained nerve supply of both. The greater facilities which the soft spleen affords for histological treatment, as compared with the hard kidney, may account for the greater success of the Golgi and other methods in the one case, and its comparative failure in the other.

The question of special nerves of metabolism, like that of special trophic nerves, which may be appropriately mentioned in this place, must be left undecided at present. That diminution of the vis a tergo necessary to push through metabolism to its normal physiological limit is the cause, rather than abnormal

explosion of physico-chemical material, of the defective metamorphosis met with in some diseases, is argued, I would suggest, by the commonly observed clinical phenomenon of deposits of uric acid, in conditions of exhaustion, in some persons who, in robuster health, exhibit the normal metamorphosis of urates. There is much more evidence in support of this view, which we shall consider more fully in its proper place. There is also a good deal of clinical and some experimental evidence to show that the nervous system has a distinct local trophic influence, although the separate existence of nerves for this purpose has not so far been established. We have so far examined the extreme periphery of the visceral nerve distribution, and found that, while there are still noteworthy upholders of the non-terminal conception of the peripheral nervous system, the balance of evidence and trend of histological opinion is in favour of the termination of the sensory and motor nerve supply of the viscera in free ends.

LECTURE II.

THE ANATOMY OF VISCERAL INNERVATION.

WHEN we strike the main stream of innervation at the apex of the visceral delta of secretory, mobile, and excretory nerve distribution, our task in tracing the current is considerably simplified. Here also, however, the threefold state referred to in the con

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FIG. 8. From the hepato-duodenal region of a mouse. (a) Large
cluster of ganglion cells; (bbb) branches; (c,c,c) ganglion cells.

ditions of the ultimate distribution is taken by the triple conditions and their associated questions, of medullated and non-medullated fibres, and of the ganglion cells, regarded as anatomical entities and conglomerate structures.

The vast majority of the fibres constituting the nerve bundles

in the branches near their ultimate distribution, are non-medullated fibres-the fibres of Remak, a term which Kölliker applies to certain fibres

[graphic]

only, of those originally described by Remak as belonging to the sympathetic system.1 These

fibres have been

C

shown by the higher powers of the microscope b to consist of many smaller

fibrils. They may be distinguished from connective tissue, according to Kölliker, by their becoming opaque, not tran

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FIG. 9.-Innervation of a bronchus from the lung of a kitten. (a) Nerve trunk with a cluster of ganglion cells; (bb) branches of (a); (c) lumen of bronchus.

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FIG. 10. From the heart of a mouse. (a) Trunk of vagus; (b) fusiform cluster or ganglion cells on (a); (c) fibres issuing from (b) as the continued trunk of the vagus; (d) fat cells; (e) hair of mouse.

1 Op. cit., Bd. ii. Hälfte 1, S. 30.

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transverse sections of those treated with. osmic acid. As

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