740 



PHYSIOLOGY. 



monkey (Macacus rhossus) the pilo-motor nerve 

 fibers for the head issue from the spinal cord in 

 the anterior roots of the third and fourth and 

 to a less extent of the second and fifth thoracic 

 nerves ; they run to the sympathetic chain, ascend 

 the cervical sympathetic, and become connected 

 with nerve cells in the superior cervical gan- 

 glion. The parts of the head affected are the 

 forehead, the front half of the scalp, the temple, 

 the cheek, and the upper part of the whisker. 

 On stimulating one sympathetic the effect * is 

 chiefly on the same side, but stretches a short 

 distance over the median line. Pilo-motor 

 nerve fibers for the buttock, thigh, and tail issue 

 from the spinal cord in the roots of the twelfth 

 thoracic, first, second, and third lumbar nerves ; 

 they pass into the lumbo-sacral sympathetic 

 chain and descend it: they are finally distrib- 

 uted in the skiti of the upper part of the but- 

 tock, the back of the thigh nearly as far as the 

 knee, and to the root of the tail. In the cat, 

 pilo-motor nerves leave the spinal cord to run to 

 the sympathetic chain in each nerve from the 

 fourth thoracic to the third lumbar: sometimes 

 also from the third thoracic nerve. Fibers from 

 the third or fourth thoracic to the seventh 

 thoracic nerve inclusive, ascend in the cervical 

 sympathetic, become connected with nerve cells 

 in the superior cervical ganglion, and supply the 

 hairs of a region between the ear and eye, and 

 of a strip of skin beginning at the back of the 

 head and extending down the back of the neck. 

 These fibers are not functional in all cats. The 

 hairs of a strip of skin of the back and of the 

 dorsal part of the tail are supplied by pilo-motor 

 fibers from about the seventh thoracic to 

 the third lumbar nerve. This strip overlaps 

 with a strip of the skin of the back about ten 

 centimetres long which is supplied by each of 

 the thoracic spinal nerves. There are reasons 

 for supposing that each spinal nerve, the roots 

 of which contain pilo-motor factors, is connected 

 with four or five sympathetic ganglia and their 

 gray rami. The second and third lumbar nerves 

 supply pilo motor fibers to the tail, and in addi- 

 tion the second lumbar nerve possibly supplies a 

 small part of the back. With any two spinal 

 nerves, from the seventh thoracic to the third 

 lumbar inclusive, the position of the maximum 

 effect on the hair is more positive with the lower 

 nerve than with the upper one. The pilo-motor 

 nerves for the tail are connected with nerve 

 cells partly in the third sacral, but chiefly in 

 the first coccygeal ganglion. Stimulation of 

 the spinal nerve or of the sympathetic chain 

 on one side gives mainly unilateral effects on 

 the back ; but in the tail the effects are usually 

 bilateral. 



Experiments by G. N. Stewart go to show that 

 the conduction in animal tissues is chiefly elec- 

 trolytic ; that the best conductors are the inor- 

 ganic constituents of the tissues, and next some 

 of the nitrogenous metabolites, while the pro- 

 teids are exceedingly bad conductors : and that 

 the proteids are affected not by primary elec- 

 trolysis, but by the products of electrolysis of the 

 salts. Further studies have been made on the 

 effects of electrolysis on isolated tissues and on 

 some of the liquids of the animal body, and the 

 effect in the living body is still under examina- 

 tion. 



Special Senses. A case bearing upon the 

 relation of the optic thalamus to the special 

 senses and to common sensibility is described 

 by Dr. Hugo Bngle, of Philadelphia. The patient 

 had felt vague symptoms of affection of the cen- 

 tral nervous system, consisting chiefly of pain 

 in the head, with occasional acute exacerbations, 

 and giddiness. One morning he staggered, and 

 associated this with loss of sensation in the right 

 foot. He next found that the whole right side 

 of his body was anaesthetic, and that he had lost 

 the power of tasting and smelling on that side. 

 Nine days later he had lost taste and smell on 

 both sides, and was deaf in both ears. Two days 

 later he became suddenly blind in both eyes, had 

 frequent convulsions, and died in one of them. 

 At the necropsy, characteristic changes were 

 found in the cerebral, and a large gummatous 

 growth, starting apparently from the fornix, 

 had been spreading back over both optic thalami. 

 It was more extensive and apparently older on 

 the left side than on the right an indication 

 that this side had been first involved in the mor- 

 bid process, which corresponded also with the 

 earlier symptoms on the right side of the body. 

 The author points out the existence of four col- 

 lections of cells in the thalamus described by Luys. 

 The most anterior, which is probably in some 

 way connected with smell : the second, possibly 

 connected with hearing; the third, with general 

 sensibility; and the fourth, in the region of the 

 pulvinar, connected with the visual tract. 



The existence of a membrane lining the fossa 

 patellaris of the corpus vitreum had been the 

 subject of discussion till it appeared to be con- 

 tradicted definitely by Schnalbe in 1886-'87. Prof. 

 T. P. Anderson Stuart has, however, informed 

 the Royal Society that he has found that in the 

 fresh, unaltered eye, after the removal of the 

 lens in its capsule, there may be raised off the 

 surface of the jelly a membrane which, when 

 strained and mounted, does not show any struct- 

 ure. When the membrane from the four-year-old 

 ox eye was isolated and tied over the mouth of a 

 test-tube |-inch wide it sustained a column of 

 water 40 inches high. A smaller column than 

 this may be sustained for days together. When 

 isolated, it may be dried to form a delicate 

 membrane. 



While the common teaching is that there is a 

 direct continuity of substance between the sus- 

 pensory ligament and the capsule of the lens, an 

 observation by Prof. T. P. A. Stuart seems to 

 indicate that the ligament is only cemented to 

 the capsule. On opening eye-balls in an ad- 

 vanced state of decomposition putrid he found 

 the lens in its capsule free, and no indication of 

 any rupture of tissue along the line of attach- 

 ment of the suspensory ligament. The liga- 

 ment was found intact projecting from the 

 collapsed vitreous body as a sort of frilled ring 

 with a free edge. 



Prof. Dubois, of Bern, studying the produc- 

 tion of luminous sensations in the human eye 

 under the action of galvanic currents, finds that 

 sudden variations of intensity, especially at mak- 

 ing and breaking the circuit, produce such 

 flashes. With a moistened plate at the nape of 

 the neck and a pad on the eye. a slight flash was 

 perceived at a very low intensity; while at a 

 considerably higher intensity the observer could 



