Ma irk I/, 1875] 



NA TURE 



377 



it is in a certain state of motion, but as soon as the radiation 

 has passed through it, the medium returns to its former state, the 

 motion being entirely transferred to a new portion of the 

 medium. 



Now, the motion which we call heat can never of itself pass 

 from one body to another unless the first body is, during the 

 whole process, hotter than the second. The motion of radiation, 

 therefore, which passes entirely out of one portion of the medium 

 and enters another, cannot be properly called heat. 



We may apply the molecular theory of gases to test those 

 hypotheses about the luminiferous a;ther which assume it to con- 

 sist of atoms or molecules. 



Those who have \entured to describe the constitution of the 

 luminiferous a;ther have sometimes assumed it to consist of atoms 

 or molecules. 



The application of the molecular theory to such hypotheses 

 leads (o rather startling results. 



In the first place, a molecular a;ther would be neither more 

 nor less than a gas. We may, if we please, assume that its 

 molecules are each of them equal to the thousandth or the millionth 

 part ol a molecule of hydrogen, and that they can traverse freely 

 the interspaces of all ordinary molfcules. But, as we have seen, 

 an equilibrium will establish itself between the agitation of the 

 ordinary molecules and those of the Kther. In other words, the 

 a;ther and the bodies in it will tend to equality of temperature, 

 and the ajther will be subject to the ordinary gaseous laws as to 

 pressure and tempeiature. 



Among other properties of a gas, it will have that established 

 by Dulong and Petit, so that the capacity for heat of unit of 

 volume of the ccther must be equal to that of unit of volume of 

 any ordinary gas at the same pressure. Its presence, therefore, 

 could not fail to be detected in our experiments on specific heat, 

 and we may therefore assert that the constitution of the Kther is 

 not molecular. 



J. Clerk-Maxwell 



SOCIETIES AND ACADEMIES 



London 



Royal Society, Feb. 18. — "On the number of Figures in 

 the Reciprocal of each Prime Number between 30,000 and 

 40,000," by William Shanks. Communicated by the Rev. Dr. 

 Salmon, F.R.S. 



"On the Nature and Physiological Action of the Crolalns- 

 poison as compared with that of Naja Irifudians and other 

 Indian Venomous Snakes," by T. Lauder Brunton, F.R.S., 

 and J. Fayrer, M.D. 



It appears that there is little difference between the physio- 

 logical efl'ects of the crotaline or viperir.e, and the colubrine 

 virus. The mode in which death is brought about is essentially 

 the same in all ; though there are evidences, even when allowing 

 for individual peculiarities, that the action is marked by some 

 points of difference sufficiently characteristic to require notice in 

 detail. 



We have already expressed our belief that death is caused by 

 the cobra-, Daboia-, and Hydrophis-'^a&oxi, 1st, through its 

 action on the cerebro spinal nerve-centres, especially on the 

 medulla, inducing paralysis of respiration ; or 2nd, in some cases 

 where the poison has entered the circulation in large quantities 

 aid has been conveyed more directly to the heart, by arrest, 

 tetanically in systole, of cardiac action, probably owing to some 

 action on the cardiac ganglia ; 3rd, by a combination of the two 

 previous causes ; 4th, by a septic condition of a secondary 

 nature, and which, being more essentially pathological in its 

 bearings, the details were not considered suitable for discussion 

 here. 



There is reason to believe that death is caused in the same 

 way by the C?-c/<r/«j-poison also ; and it appears, from the 

 experiments recently performed in Calcutta by Dr. Ewart and 

 the members of the Committee appointed by Government upon 

 rsaiduhis porphyriacus, or the black snake, and Hoplocephalus 

 curlus, or the tiger-snake of Australia, that their virus causes 

 death in the same manner. These reptiles had been sent from 

 Melbourne to Calcutta for the purpose of investigation and com- 

 parison. i^Vide Committee's Report, p. 58 d sn].. Appendix.) 



But though the actu.al cause of death is essentially the^same, 

 the phenomena which precede and accompany it differ in some 

 degree according to the nature of the poison, the quantity and 

 ite of the inoculations, and the lindividual peculiarities of the 



creature inoculated, as may be seen in the expeiiments herewith 



recorded. 



The condition of an animal poisoned by the rattlesnake- 

 venom, then, essentially resembles that of ore subjected to the 

 influence of the colubrine orviperine poison of Indian snakes : — 



Depression, hurried respiration, exhaustion, lethargy, uncon- 

 sciousness, nausea, retching, and vomiting. 



Muscular twitchings, ataxy, paralysis, and convulsions, the 

 latter probably chiefly, though not entirely, due to circulation of 

 imperfectly oxygenated blood, the result of impeded respiration, 

 and, finally, death. 



Hemorrhages or hemorrhagic extravasations and effusions, 

 both local and general, occur in all varieties of snake-poisoning. 



But we observe (and in this our observations are in accord with 

 those of Weir Mitchell) that there is a greater tendency to both 

 local and general hemorrhage and extravasation of blood and of 

 the colouring matter of the blood, especially as observed in the 

 peritoneum, intestines, and mesentery, and also prob.abIy to a 

 more direct action on the cord than in poisoning by either cobra 

 or viper. 



Tlie viscera and other tissues^atler death are found congested 

 and ecchymosed, ard in some cases to a great extent, seeming to 

 show that either a preternatural fluidity of blood or some 

 important change in the vessels, favouring its exudation, has 

 occurred. 



Several experiments were made on the physiological action of 

 the virus of the rattle-snake, with the view of comparison with 

 that of the cobra and Daboia. 



We are indebted to Dr. Weir Mitchell, of Philadelphia, for a 

 sui jily of the virus. lie was good enough to send about six 

 grains of the dried poison of Crotalus — the species not named, 

 but it is believed to be of Crotahis durisius. 



It has the appearance of fractured fragments of dried gum- 

 arabic and of rather a darker yellow colour, but otherwise 

 resembling the dried cobra-virus sent from Bengal. 



There were no very marked differences to be observed in the 

 action of the poison except in the energy with which the cobra 

 exceeded the Crotalus. 



It appears that the direct inoculation of large doses of the 

 virus, whether viperine or colubrine, into the circulation have 

 the power in some cases of annihilating almost instantaneously 

 the irritability of the cord and medulla, as in others they have of 

 arresting the heart's action. 



The local as well as the general effect of the cobra- and Cro- 

 /(;/;M-poisons, i.e. colubrine and viperine, is to cause hemorrhage, 

 ecchymosis, and sanguinolent effusions into the areolar tissue, not 

 only at the scat of inoculation and its neighbourhood, but also in 

 the mucous membranes and other vascular parts. It is obvious 

 also that the Crotalus--fo\i,on acts more energetically in this respect 

 than the cobra-poison, and that this is perhaps one of the most 

 marked distinctions between them. 



Cobra venom is a muscular poison, and the gastrocnemius of 

 a frog immersed in a watery solution of it contracts immediately 

 upon immersion, and loses its irritability very much sooner than 

 one placed in pure water. 



In our experiments cobra-poison appeared first to stimulate 

 and then to paralyse the motions, ol cilia from the mouth of 

 a frcg. 



It arrests very rapidly the movements of infusoria and of the 

 cilia upon them, but the cilia upon the mantle of a fresh-water 

 muscle continued to move for many hours in an extremely strong 

 solution of dried cobra-venom. In the case of white blood-cor- 

 puscles no veiy distinct action was observed. When applied to a 

 piece of Vallisticria spiralis it appeared to have almost no effect, 

 for the motion of the granules within the cells continued witli 

 undiminished rigour for two hours afterwards. 



Feb. 25. — "On the Forms of Equipotential Curves and Sur- 

 faces and Lines of Electric Force," by W. Grylls Adams, 

 M.A., Professor of Natural Philosophy and Astronomy in 

 King's College, London. 



Tlie paper contains an account of certain experimental verifi- 

 cations of the laws of electrical distribution in space and in a 

 conducting sheet, such as a sheet of tinfoil. When two battery 

 poles are attached to any two points of an unlimited plane sheet, 

 or to two points on the edge of a circular disc, or if the disc be 

 bounded by arcs ol circles passing through the two batteiy poles, 

 the lines of force and also the equipotential curves are circles. 

 The equipotential circles have their centres on the straight line 

 joining the battery poles, and the lines of iorce pass through 

 these poles. In any limited space, whether in the plane or in 



