September 15, 1898] 



NATURE 



483 



Prof. Gotch, F.R.S., and Mr. G. J. Burch (Oxford) showed 

 photc^raphs of the electrical response of nerve to excitation. 

 The results obtained have been : Biphasic effects indicated by 

 a rapid displacement in one direction which is followed by one 

 in the other. Examples of these are (i) effect in uninjured 

 fresh nerve with both contacts upon the surface, (2) effect in 

 excised nerve kept for twenty-four hours in 0'6 per cent, NaCl. 

 Monophasic effects indicated by a rapid displacement returning 

 very slowly and exhibiting a second effect of similar direction 

 but of slow development, the negative after-effect obtained when 

 the functional capacity of the tissue under the distal contact is 

 so lowered that it is incapable of undergoing the change which 

 produces the excitatory electrical response. Biphasic effects 

 with prolonged second phase when the functional capacity of 

 the tissue is low ; the records show an initial small displace- 

 ment followed by a prolonged one of opposite sign, i.e. a 

 positive after-effect. The nerve when excited by a rapid series 

 of stimuli gives a series of independent spikes ; the injured 

 nerve gives a series of displacements which are superimposed ; the 

 aftereffect not having subsided when the second response occurs. 



Prof A. B. Macallum (Toronto) brought forward and illus- 

 trated by demonstration his method for detection and localisa- 

 tion of phosphorus in animal and vegetal cells, &c. The use 

 of pyrogallol for this purpose is not free from objection, and a 

 reagent was sought which would definitely distinguish between 

 the molybdate and phospho-molybdate of ammonia. This 

 reagent was found in phenylhydrazin hydrochloride in a 1-4 

 per cent, aqueous solution which gives a dark-green reaction 

 with the phospo-molybdate compound, but none with molybdate 

 of ammonia in the presence of nitric acid. The nitric-molyb- 

 date reagent is allowed to act for some hours at a slightly 

 elevated temperature on the sections of tissue, which are then 

 transferred to the solution of phenyl-hydrazin hydrochloride. To 

 prevent the confusion which might result from the presence of 

 lecithin, the latter must be extracted with hot alcohol, frequently 

 renewed, for five hours, and the presence and amount of in- 

 organic phosphates are indicated by the early appearance of the 

 reaction and its extent. 



The method has resulted in demonstrating the presence of 

 " masked " phosphorus in the chromatin of all animal and 

 vegetable cells, in nucleoli, in the anisotropic substance in 

 muscle fibre, in the prozymogen and zymogen of pancreatic 

 cells, in the colloid material of the thyroid, in the outer limbs 

 of the rods and cones, in pyrenoids of the Protophyta, &c. It 

 also shows that in non-nucleated organisms like the Cyano- 

 phyceiE and Saccharomyces the phosphorus-holding substance, 

 or nucleo-proteid, although sometimes in the form of granules 

 or spherules which have been taken for nuclei, is frequently 

 dissolved in the cytoplasm. 



Prof. Boruttau (Gottingen) communicated a paper upon 

 recent advances in electro-physiology. After speaking of the 

 methods of investigating the course in time of the action-current 

 of nerve, and especially of the use of combining photographic 

 records with rheotom experiments, he discussed the biphasic and 

 monophasic action-currents of frog's nerve, their modifications 

 in electrotonus,ftheir alteration and abolition under ether narcosis 

 and in cold, their increase by COj, the alterations effected in the 

 electrotonic state by ether and by COj, and the phenomena of 

 the curare preparation. 



Prof. J. B. Sanderson (Oxford) communicated a paper on the 

 duration of the monophasic variation of the sartorius muscle of 

 the frog. 



Dr. Theodore Beer (Vienna) brought forward an important 

 communication, richly illustrated by experiment, upon the 

 accommodation of the eye in various species of the animal king- 

 dom. In order to adapt an eye to a range of objects at different 

 distances, two plans are employed. In the first the curvature 

 of the refracting surface is made adjustable ; in the second the 

 distance of the refracting surfaces from the receptive screen is 

 adjustable. The adjustment of the curvature is exclusively of 

 increase of the curvature, affording thus an active accommoda- 

 tion for near vision. This exists in mammals, birds, lizards, 

 crocodiles, tortoises, and in a few snakes. Throughout the above- 

 named forms the means by which the adjustable increase of 

 curvature is obtained is by the active contraction of a muscle 

 slackening the suspensory apparatus that under the resting con- 

 dition of the muscle keeps to some degree flattened the anterior 

 surface of the lens. 



In cephalopods and the bony fishes the eye is when at rest 

 in focus for objects near at hand. In these forms the adjust- 



ment is for distant objects, and is brought about by the retreat 

 of the lens towards the retina. In amphibia and snakes— or 

 rather in such of them as possess any visual accommodation- 

 there exists an active accommodation for near vision executed 

 by an advance of the lens from the retina. In the bony fishes a 

 special muscle {Retractor lentis. Beer) drags the lens backwards 

 towards the retina. In the cephalopods, amphibia and snakes, 

 alterations in intraocular pressure, brought about by contraction 

 of circularly-arranged muscle-fibres, play an important part. 

 Among mammals, reptiles, amphibians, and fish there are cer- 

 tain species that have no power of visual accommodation ; these 

 are for the most part nocturnal species and forms with narrow, 

 even slit-like pupils (great sensitivity to light). Some of the 

 tortoise-tribe, which dive under water, not only counterbalance 

 the loss of the corneal refracting surface thus occasioned, but 

 even under water accommodate for near vision. 



Prof. Halliburton, F.R.S., and Dr. F. W. Mott, F.R.S. 

 (London) demonstrated the influence of cholin, neurine, and 

 some allied substances upon the arterial blood-pressure. Ii> 

 certain diseases of the central nervous system the cerebrospinal 

 fluid becomes laden with toxic substances of this class, and it is 

 in prosecution in that direction that the researches of Profs. 

 Halliburton and Mott are especially suggestive. 



Prof. E. Weymouth Reid, F.R.S., and Dr. J. S. Macdonald 

 (Dundee) demonstrated experiments illustrative of their study of 

 the electromotive changes in the phrenic nerve. 



Electromotive changes in the phrenic nerve can be demon- 

 strated to accompany the groups of nervous impulses periodically 

 generated in the respiratory centre. By the cut end and a point 

 about a centimetre central thereto, the nerves are suspended on 

 "cable" non-polarisable electrodes, free of the tissues of the 

 neck, and are led off to the galvanometer (without compensa- 

 tion) or capillary electrometer. A single nerve, or, taking sym- 

 metrical points on the two sides, both "in parallel" (galvano- 

 meter) or "in series " (electrometer) may be used for experiment. 

 The characteristic effects have been seen as long as two hours 

 after putting the nerves in circuit. Intermittent electrical dis- 

 charges (negative variations of the demarcation current) are ob- 

 served and can be abolished by ligature of the nerve with moist 

 thread above the proximal electrode. If the animal is curarised 

 and artificial respiration set up, it is found that the magnitude of 

 the discharge is directly affected by the supply of air, so that with, 

 over-supply there is cessation of discharge, with uoder-supply or 

 stoppage of pump, asphyxial increase. 



Prof. Sherrington, F.R.S. (Liverpool), with Dr. Hering. 

 (Prague), gave a convincing demonstration in the monkey 

 \Macacus) of inhibition of the contraction of voluntary muscle 

 evoked by electrical excitation of certain points of the cortex 

 cerebri. This inhibition, producing relaxation of volitional 

 muscles, was shown to occur regularly in the evocation of co- 

 ordinated movements from the cerebral cortex. The relaxation- 

 of a muscle is not obtained by excitation of the same point of 

 cortex as that whence its contraction is elicitable, but is obtainable 

 from the same point of cortex as that whence contraction of its 

 antagonist can be obtained. A distance of more than a centi- 

 metre sometimes separates the points whence contraction and 

 relaxation of one and the same muscle can respectively be 

 obtained. Besides this reciprocal innervation of the true 

 antagonists, evidence was demonstrated of a more complex 

 relationship between different muscle groups; relaxation of 

 some muscles and contraction of others was shown to exist in 

 cases where the physiological connection between the two 

 different activities is not obvious or easily intelligible. 



Dr. Maurice Nicloux (Paris) showed that if carbonic oxide is 

 made to pass over iodine anhydride maintained at a temperature 

 of ioo°-i5o°, the carbonic oxide is oxidised, and passes off in 

 the form of carbonic anhydride at the same time that the iodine is 

 set free in corresponding quantity. This reaction occurs what- 

 ever be the dilution of CO in the air, even if the dilution be 

 50,000. Search for traces of CO becomes, therefore, simple, 

 rapid and exact. There is, therefore, a certain amount of CO 

 normally in the blood. The average quantity seems to be i '4 

 cc. per litre of blood. M. Desgrez has shown that chloroform 

 in contact with an aqueous solution of potassium produces some 

 carbonic oxide. The general reaction of the blood and tissue 

 fluids being alkaline, Nicloux and Desgrez have inquired 

 whether this decomposition does actually occur in the organism. 

 Experiment has shown that it does. 



Prof. Marey (Paris) showed a new series of studies in chrono- # 

 photography. 



NO. 1507, VOL. 58] 



