SOCIETY, PHYSIOLOGICAL December 11, PROCEEDINGS. (Preliminary communication.)

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1 PROCEEDINGS QF THE PHYSIOLOGICAL December 11, SOCIETY, A muscle twitch lasting for hours. By K. FURUSAWA. The longitudinal abdominal muscle of Holothuria nigra, put in diluted sea water (10-20 p.c.), can respond to a single induction shock, and it requires several hours to relax completely. The contraction has the following properties: (1) the time required to reach a maximum is the same order as that in undiluted sea water; (2) the rate of relaxation depends upon the force exerted on the muscle; (3) this contraction can be set up repeatedly without any sign of fatigue; (4) the pull response during contraction is quite different from that which Hill and Gasser found with frog's muscle; (5) complete recovery of normal function is observed in sea water. The influence of one coloured light on the sensitivity of the eye to the same and other colours. By H. E. ROAF. From the Department of Physiology, the London Hospital Medical College. (Preliminary communication.) If different regions of the spectrum excite different retinal mechanisms they should have comparatively little effect on each other. The degree to which one light interferes with another may be considered as a measure of the extent to which they act on similar mechanisms. In the results that follow the sensitivity is measured by the threshold to the coloured light Ėxposure of one part of the retina to light has a general effect in decreasing the sensitivity of other parts: this is the effect on the darklight adaptation of the eye. All regions of the spectrum have a similar effect on the adaptation of the eye, namely that they decrease the sensitivity to blue and violet most, green next, and have very little effect on red. When, however, the two lights stimulate the same area of the retina special differences are noted. Red light decreases the sensitivity to all regions of the spectrum. Green light decreases the sensitivity to green V'

2 xxii PROCEEDINGS OF THE PHYSIOLOGICAL and blue, but has little effect on red. Blue light has most effect on the sensitivity to blue, less on that to green and least on that to red. These results differ from those of Burch(l), who says that the fatiguing light has an effect only on its own region of the spectrum. They also differ from the results of Troland(2), who states that " minuthesis due to one colour does not alter the luminosity of another colour to a degree differing appreciably from that in which it is altered itself." A ll e n (3) finds that exposure of the eye to coloured light affects several regions of the spectrum, but that there are certain transition colours at which no effect is produced. A practical application of the results is that a blue screen is the best to protect the eyes from other lights, e.g. when motoring. (1) Burch, G. J. Phil. Trans p (2) Troland, L. T. Abstract Bull. Nela Res. Lab. General Electric Co. Cleveland. p (3) Allen, F. (Latest paper.) Journ. Optical Soc. Amer. 13. p Toxaemia from Liver Grafting. By D. T. BARRY and J. FREUD. Arising from an investigation of the role of the liver in the regeneration of blood after haemorrhage, in which one of us was engaged some time ago, we were led by the condition of dogs grafted with liver substance to test the effects of their blood on other animals. Grafted intraperitoneally the animals generally showed symptoms of depression according to the weight of liver used in proportion to body weight. In those where three to five grams of liver from freshly killed dog were used per kgm. the results were all fatal after intervals of from 24 hours to three days (four experiments C, D, E, T). When the size of the graft was reduced to about 2-5 or 3 grams per kgm. it was again fatal in all cases, but two lasted five days (five experiments, F, G, H. J, M; J being a female with pup near term). When the graft amounted to about one gram per kgm., not exceeding 1-5 grams, a fatal result occurred in one (S) on the third day (five experiments K, L, S, U, V). U and V were killed for blood on the second day; and K and L were allowed to live for 15 days in apparently perfect health, when they were regrafted. No graft was actually weighed but similar pieces were. Table I comprises a few of the protocols showing the very toxic effects of the blood of grafted animals on others. The poison is elusive, occurs at a certain interval after operation and lasts a limited time. The earliest period in which it was found to be toxic was seven hours

3 SOCIETY, DECEMBER 11, xxiii after operation, and the latest twenty-eight and a half hours after grafting. We express no opinion as yet about the nature of this poison. Exposure and agitation of oxalated blood caused disappearance of toxicity in one sample, clotting caused disappearance in another, heating to 560 C. in a third. Death in the poisoned animals is very characteristic: respiratory spasm, cry, rigidity, stiffening of head and tail, post mortem twitchings are prominent signs. Positive effects from intravenous injection of this toxic blood were obtained in three cases without causing death, while the characteristic death described resulted in ten cases (nos. 1, 2, 5, 6, 14, 15, 16, 17, 18, 19), a sufficient number to establish the main fact with certainty. Table I. Some Protocols of Experiments. Index D. 5*5 K. Series I. Condition Date 15/11/26... Young, normal Toxicity for Others. Operation 30 gm. liver perit. cav. Do /11/26... Very weak Bled (full) G. 6K... 20/11/26... Healthy, 15 gm. liver young perit. cav. Do /11/26... Very good 5 cc. blood from ear Observations Recovered well 10 cc. fatal to No. 1, 20 sec. Well at once... Blood fatal to dog 6-5K. (20 sec.) Easy rapid op. Inj. no. 5 (lact.) Inj. no. 6 (ord.) Rapid recovery J. 9K... 24/11/26... With pup, 12 gm. liver? near term perit. Do /11/26... Good... 10cc. bl. ear Do.... Do.... Do cc. bl. ear L. 5-5K. 24/11/26 Young, 7-8gm. iver d normal perit. Do /11/26... Good... 5 cc. bl. ear Inj. no. 5 (lact.) V. 4iK. 6/12/26... Healthy, 6 gm. liver a.m. young perit. Do. Do. 4 p.m. - 10cc. bl. ear Inj. no. 14 Do.... (11 K.) Do. 7 p.m cc. bl. ear Inj. no. 14 General Remarks Soon became weak. Death 24 hrs. Toxicity 18 hrs. P.M. 50 cc. choc. fluid in peritoneum. Very well three daysthen death on 4th day. Blood of dead dog nontoxic. Toxicity 20 hrs. Took food very soon, had seven puppies next day. No effect on no. 5 (7k.). Death of no. 6 in 40 sec. Took food etc. soon after op. Toxic 20 hrs. Death of no. 5, 40 sec. Quick recovery. Toxic 7 hrs. Resp. effects only. Death 1 min., cry, rigid. Impulses in the optic nerve. By E. D. ADRIAN and RACHEL ECKHARD. (Preliminary communication.) The electric responses developed in the retina on exposure to light have been studied repeatedly. They are complex changes, generally regarded as made up of three or more components, and though they give a valuable index of the activity of the retina they give no information

4 xxiv PROCEEDINGS OF THE PHYSIOLOGICAL as to the form in which this activity is transmitted to the brain, i.e. as to the nature of the impulses in the optic nerve fibres. The short length of the optic nerve and the large number of fibres in it makes it less easy to record the electric responses than is the case with a peripheral sensory nerve, but we have succeeded in doing so in the optic nerve of the conger eel (Conger vulgaris). This nerve contains relatively few fibres (under 10,000) and may be as long as 2 cm. The isolated eye and optic nerve preparation is arranged with electrodes leading fromn two points on the nerve to a three or four valve amplifier and the capillary electrometer. An opal glass screen is illuminated by a lamp at varying distances, the area of the screen is controlled by an iris diaphragm and its image can be focussed on the retina by lenses. As a rule the nerve is free from action currents when the eye is in darkness, but on illumination a rapid series of oscillations appear in the record (Fig. 1). The usual controls have l.. ~1#005- lool sec.} Fig. 1. A. Action currents in optic nerve on exposure to light. Film record. Time marker (white lines) gives intervals of a sec. Light turned on just before film begins. B. Ditto, plate record. Time marker (above) gives ih sec. intervals. Fig. 2. Analysis of another electrometer record showing time relations of action currents. T = 16 C. been made to exclude artefacts. Analysis of records on plates moving at 80 cm. per sec. shows an irregular succession of mono- or diphasic action currents each lasting for about '0015 sec. The majority seem to conform to a standard size and duration though there may be considerable overlapping. The maximum frequency occurs at or near the beginning of the response and declines rapidly. There is usually a renewed outburst of impulses when the light is turned off (as there is in the retinal

5 .SOCIETY, DECEMBER 11, =t response). The frequency on illumination varies with the area and the intensity of the light, though we are not yet in a position to give accurate values. Owing to the rapid decline in frequency with steady illumination a moving light or shadow produces a much greater effect than a stationary light. Points of some interest have arisen in connection with the latent period, the frequency in each fibre, etc., but our records leave no doubt that the discharge in the optic nerve is of substantially the same type as that in other sensory nerves. This is illustrated in Fig. 3, which 4 :' :~~~~~~~~~~~~~~~~~~~~~~~~~~~~1 :, ;4 Fig. 3. A. Action currents in optic nerve on exposure to light. B. Action currents in frog's sciatic produced by tension on gastroonemius. compares the response in the eel's optic nerve with that in the frog's sciatic when the gastrocnemius is stretched. Apart from the larger size of the action currents in the sciatic (which has fewer fibres) the records are almost indistinguishable. The ultra-violet absorption spectra of cerebro-spinal fluids. By F. CAMPBELL SMITH. (Preliminary note.) Judd Lewis in 1922 obtained the quantitative absorption spectra of the serum proteins, and in 1923 Ward obtained those of some of the more important amino acids. Other workers have since shown that the absorption bands of proteins are due to the amino acids contained within their molecule. Cerebro-spinal fluid has the following advantages over the other body fluids in this type of work: 1. It canbeobtained directlyfrom the subject without contamination. 2. It is optically clear.

6 xxvi PROCEEDINGS OF THE PHYS. SOC., DEC. 11, The concentrations of protein and other substances in it are within the range of the Hilger sector photometer and so it does not require dilution. 4. It is free from pigment, both in the normal and majority of pathological conditions. It is, therefore, the one body fluid which can be investigated by this method without the risk of introducing error by manipulative technique. The normal absorption curve has been obtained and compared with those of various pathological conditions. Curves which appear to be typical of tuberculous meningitis and of tabes dorsalis respectively have been found. It is suggested that the method may be of diagnostic value. The curves and details of the technique will be published in a subsequent communication.