596 



SCIENTIFIC NEWS. 



[June 22, iJ 



THE CAUSATION OF VITAL MOVE- 

 MENT. 



THE Croonian Lecture for 1888 was delivered on May 

 28, before the Royal Society by Dr. W. Kiihne, 

 Professor of Physiology in the University of Heidelberg, 

 in the theatre of the Royal Institution, kindly lent by the 

 managers, for greater convenience of illustration by lan- 

 tern, by diagram, and by experiment. Professor Kiihne 

 has for thirty years carried on laborious and persevering 

 researches into the terminations of nerves in muscles and 

 the ultimate structure of muscles in many classes of 

 animals, and much of his work is of the highest value. 

 His lecture consequently excited great interest among 

 physiologists, and although he preferred to deliver it in 

 German, an English translation which was distributed 

 among the audience was of essential service in grasping 

 the difficult subject, " The Causation of Vital Movement." 

 At the outset the Professor disclaimed the old idea that 

 vital movement was a special animal function, whereas it 

 is an attribute of all hving matter. The unitary concep- 

 tion of life for which the age is distinguished rests in a 

 higher degree on a knowledge of vital processes than is 

 commonly recognised, and is just as much founded on 

 physiological experience as on that of the forms of the 

 organism. This is quite true of movement, the lecturer 

 maintained. Movement is an attribute of protoplasm, 

 both of animals and plants, and it is impossible to have a 

 cell which does not preserve it at some time or other. 

 This movement is a spontaneous activity which may go 

 on in opposition to gravity, and which overcomes fric 

 tional resistance. Its cause can only be internal, and can 

 only consist in chemical processes taking place within 

 the protoplasm itself. But are these processes first set 

 up by something coming from the outside, and deter- 

 mining the variability of the process ? Physiological in- 

 vestigation has shown that protoplasm is irritable— that 

 is, it reacts to stimuli, just like muscle; and electrical 

 stimulation especially, the most indispensable instrument 

 of physiology, first strengthens the movements, then 

 brings the mass into a form with the least surface— i.e., 

 a sphere, in prolonged maximal contraction. We are 

 compelled to regard all movement as either originating 

 automatically or by direct external stimulus. The first 

 idea of an observer, that something like will actuates 

 even the lower protozoa, must be checked by our finding 

 precisely the same phenomena in the colourless corpus- 

 cles of human blood, and the protoplasm of a plant-cell, 

 and by contemplating the rhythmically contracting cells 

 from the beating heart of a bird's egg after only a couple 

 of days' incubation. Many causes of this motion are in 

 recent times found to be non-essential ; even oxygen can 

 be dispensed with by many objects for lengthened 

 periods. The lecturer detailed the del'cate gradations 

 between the most formless protoplasm, through flagella 

 and cilia, and the primitive muscles of infusoria to the 

 highest forms, showing that they possess a complete set 

 of vital powers, excepting that of reproduction ; while 

 fully developed muscle is actually poorer by one 

 power than elementary protoplasm, for it is wanting in 

 automatism ; thus protoplasm as opposed to muscle 

 possesses elementary nervous properties. The muscle- 

 cell is incomplete without the nerve-cell connected with 

 it by the continuous nerve-fibre, which may be several 

 feet long. Thus we have two separate cells united only 

 for one purpose; one is the exciting nerve, the other 

 the obedient muscle. Without concerning himself 

 about the excitation of the nerve-cell, the lecturer 



devoted himself to considering whether the muscle- 

 cell can be stimulated otherwise than through the 

 nerve. The affirmative answer disposes of the ani- 

 mistic or neuristic view that the excitation and 

 regulation of the various functions is everywhere the 

 work of the nervous system. The ubiquity of nerve- 

 branches has been disproved by exhaustive researches, in 

 which Professor Kiihne has borne a part. He showed 

 experimentally that small pieces of fresh frog's muscle 

 in which no nerve can be detected by osmium-gold stain- 

 ing, which displays the finest nerve-fibres, yet twitched 

 at each effective stimulus. He also demonstrated the 

 incorrectness of the assertion that everything that excited 

 the nerve made the muscle twitch, and vice versa. A 

 further series of experiments showed that motor nerves 

 can conduct centripetally, that the absence of nerve? 

 from a portion of muscle can be absolutely proved by a 

 physiological test, and that it is not possible to excite the 

 motor nerve of a muscle-fibre by any stimulus to the 

 nerve ends within the fibre. Moreover, the excitement 

 or contraction of a muscle does not travel back into its 

 nerves. Professor Kuhne has proved the vastly pre- 

 ponderant number of muscle-fibres is entirely free from 

 nerves, and that the nerve endings are confined to very 

 small tracts, termed fields of innervation. Consequently 

 it is proved that muscle-fibre shares with nerves the 

 property of propagating its own excitation, the velocity 

 of conduction being from one-third to one-tenth of what 

 it is for nerves. Thus the nerve only introduces a 

 stimulus to the muscle, which propagates it by its own 

 independent irritability in every movement and through- 

 out life. All the stimuli, except the gaseous, which can 

 act on muscle appear capable of being resolved into the 

 setting up of electrical cjrrents, and thus, said the 

 lecturer, we find ourselves in the presence of the possi- 

 bility of reducing all irritability to a reaction to electrical 

 processes, and of seeing vital electricity elevated into 

 immeasurable importance. Going on to discuss the 

 precise endings of nerves in muscles as essential in con- 

 sidering how nerve acts on muscle, Professor Kiihne 

 showed diagrams from microscopical preparations which 

 he had on exhibition, indicating in many animals the 

 superficial nature of nerve endings in muscles, the hooked 

 forms of their branches, turned as a rule towards each 

 other, and the direct contact of the nerve end with either 

 the transversely striped contents of the fibres or with 

 the protoplasmic sarcoglia which traverses and pene- 

 trates it. The muscle-wave begins in the field of inner- 

 vation, and has indeed been caught and fixed at the very 

 beginning by sudden hardening of muscles. Professor 

 Kiihne then referred to the discoveries of Du Bois-Rey- 

 mond in the following terms : — "The celebrated champion 

 of electro-physiology has been able with the galvano- 

 meter to render the excitation of nerves, unattached to 

 muscles or ganglion-cells, evident as the negative varia- 

 tion of the natural nerve current, to cause movement of 

 a magnetic needle instead of a muscle, or to put the 

 needle in the place of sensation." The currents of action 

 of muscle have long been proved to excite nerves, and 

 there are similar effects from nerve to nerve. Professor 

 Kiihne showed how he had succeeded in practically 

 uniting two muscles, the nerves of which had been dis- 

 posed of by poisoning with curare, so that the muscles 

 acted as one. Stimulation and contraction were propa- 

 gated from one end to the other. Any electrical insula- 

 tion between the muscles stopped the current, conse- 

 quently the first muscle must previously have excited 



