January 30, 1902] 



NATURE 



309 



well worthy of careful perusal, and in a short paragraph only 

 the very salient points can be touched upon. The author begins 

 with a plea for centralisation and a note of warning against the 

 multiplication of universities, when ample means are not to 

 hand for their equipment. Local convenience is undoubtedly 

 an important consideration, as is also emulation between 

 districts for the possession of intellectual centres, but both of 

 these should be subordinate to the true interests of education. 

 The equipment of the modern university is necessarily a very 

 costly matter. The next point we can consider is the length of 

 the medical curriculum. Prof. Wilson directs attention to the 

 value of general education to the medical student, and views 

 with regret the abolition by many universities of the obligatory 

 preliminary degree in " Arts." In this connection he refers to 

 the new regulations at Harvard, in which it has been enacted that 

 the medical student shall undergo a preliminary four years' course 

 in arts before entering upon bis four years' medical curri- 

 culum. In view of the present controversy concerning elemen- 

 tary medical education, it is of interest to note that the author 

 appears to accept the general educational value of special 

 medical studies, but is apparently not in favour of the relegation 

 of physics, chemistry and biology to the schools. The chief 

 reason against this is the assumption that it would still add 

 another year to the curriculum, and " this might be as well 

 done frankly under university guidance." It may be objected, 

 however, that the boy could perfectly well begin these studies 

 at sixteen, and it is certainly a very open question whether at 

 such an age he is better at the school or university. With 

 regard to pharmacology. Prof. Wilson would relegate the ex- 

 perimental part entirely to the physiologist and the therapeutical 

 part entirely to the physician. lie apparently does not see in 

 pharmacology as at present taught what he describes so accurately 

 in the case of general pathology, namely, a ' ' bridge-like " position 

 in the medical curriculum, fitting the student, when essentially 

 pursuing the intermediary subjects, for the problems awaiting 

 him in the wards, and enabling him to utilise to the full the 

 relatively small clinical experience which he will obtain. In 

 conclusion. Prof. Wilson admits that the medical curriculum is at 

 present full to overflowing, and recommends a somewhat novel 

 plan to relieve it. He suggests, and instances certain American 

 universities as precedents, a more universal use of the honours 

 system. He would establish a system of "elective studies," 

 would allow the student to specialise earlier in his career, and 

 while demanding certain evidence of all-round knowledge, 

 would very considerably reduce the standard in it, according to 

 the depth and thoroughness of the work done by the student in 

 certain directions. It must be admitted, however, that the 

 magnitude of the irreducible minimum would be difficult to 

 decide, as would also the thoroughness of " work done by the 

 student in certain directions." 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, May 23, 1901. — " On the Intimate 

 Structure of Crystals. Part v. — Cubic Crystals with Octahedral 

 Cleavage." By Prof. W. J. Sollas, F.R S. 



November 21, 1901. — "On Skin Currents, Part ii. Ob- 

 servations on Cats." By Augustus D. Waller, M.D.. F. K. S. 



In part i. it was stated that the normal electrical re- 

 sponse of frog's skin to excitation is outgoing, from internal to 

 external surface. In the skin of the pad of the cat's foot the 

 electrical effect of exciiation of the sciatic nerve proved to be 

 ingoing, as slated by Luchsinger and Hermann. Dr. Waller 

 determined this fact by decapitating cats and immediately testing 

 the effect of excitati<m of the sciatic nerve on the pad of the 

 foot : the effect gradually declines and disappears an hour after 

 decapitation. It is pointed out that this experiment on a freshly 

 killed animal is a convenient class demonstration of a funda- 

 mental fact which it has hitherto been thought necessary to 

 demonstrate on living animals. The effect is elicited after the 

 sciatic ha-s ceased to provoke muscular contraction; the largest 

 response observed and photographed was '0100 volt, the lost 

 time was three seconds. 



In order to observe the response to direct exciiation, the pad 

 of a car's foot was cut off and set up between unpolarisable 

 electrodes; during the first forty-eight hours there is a normal in- 

 going current of oioo volt. If after exact compensation of this 



NO. T683, VOL. 65] 



current a single induction current is sent in in either direction, 

 the after-effect is nearly always outgoing, as in frog's skin ; an 

 ingoing effect is observed with a fresh skin and weak excitation. 

 Dr. W^aller thinks it probable that both ingoing and outgoing 

 forces may co-exist in the excited skin, the galvanometer ex- 

 pressing the resultant. In order to investigate the causes of 

 the variability of the direction of response, the ABC method is 

 devised : — Three electrodes are applied to the external surface 

 of the skin, the third electrode C being used to examine sepa- 

 ately the effects at A and B. By means of an especially designed 

 switch called the M-shaped switch, an excitation can be applied 

 at A and B, and the response led off through C and A, or Cand 

 B. The response is found to be always an outgoing current at 

 A or B for both directions of excitation. 



Physical Society, January 24. — Prof. S. P. Thompson, 

 president, in the chair. — A paper on the factors of heat was 

 read by Mr. James Swinburne. In all branches of physics, 

 except heat, energy is divided into pairs of factors. Heat is 

 generally thought of as a sort of indivisible energy and is not 

 split into factors, but is treated as a whole, so that we have con- 

 ductivity for heat, capacity for heat, specific heat, &c. Capacity 

 for heat and specific heat are also taken when they include 

 external work, at constant pressure for instance ; so that the 

 capacity is reckoned as capacity for energy which is only partly 

 in the body or substance. So little is heat realised as energy 

 that it has its own unit, so that equations involving other forms 

 of energy with it need to be complicated with a coeflicient. 

 Temperature might be a factor of heat, but there is no cor- 

 responding quantity factor. There is no unit of temperature, 

 it is measured in degrees which have no proper connection with 

 anything. Temperature is sometimes treated as a tension factor 

 with heat as the quantity factor, as when heat is said to run down 

 temperature. Heat is thus regarded as its own quantity factor. 

 Entropy is sometimes incorrectly used as the quantity factor cor- 

 responding to temperature. Entropy is at present indispensable 

 as a function involving information as to whether heat has been or 

 might have been converted into work. The author discusses 

 " chy ' as a possible factor for use with absolute temperature 

 where " chy" is a quantity factor such that when multiplied by 

 the temperature at which it is added or withdrawn gives the 

 energy added or withdrawn. In the 9, x system capacity, 

 specific capacity and conductivity vary inversely as the temper- 

 ature. These factors are not analogous with the factors of other 

 forms of energy and are not convenient. The energy of heat is 

 therefore split into t it, where t is proportional to the square 

 root of the temperature and is called by the author "tasis. " 

 The other factor, ir, is called "posot. " In any gas, tasis is pro- 

 portional to the effective velocity and posot to the momentum. 

 Tasis and posot are analogous to the tension and quantity 

 factors already in successful use and indispensable in the treat- 

 ment of other forms of energy. Conductivity of posot follows 

 Ohm's law and the capacity of a body for posot is constant. 



Chemical Society, January 16. — Prof. J.Emerson Reynolds, 

 V.P.R.S., president, in the chair. — An investigation of the radio- 

 active emanation produced by thorium compounds, by Prof. 

 Rutherford and Mr. Soddy. The authors have previously 

 shown that whilst thoria gives rise to a Becquerel radiation, it 

 also communicates to gases passed over it a radio-active sub- 

 stance referred to subsequently as the emanation. They find 

 that the emanating power of the oxide is destroyed by heating 

 and can be restored by reprecipitation, and, further, that 

 probably the emanating power is not a specific property of 

 thoria, but is due to the presence of some foreign substance. 

 As regards the nature of the emanation itself, it appears to be 

 a gas of the argon type, since it is not destroyed by such 

 powerful agents as red-hot lead chromate, white-hot platinum 

 black, red-hot magnesium, &c. — The constitution of hydro- 

 cyanic, cyanic and cyanuric acids, by Dr. F. D. Chaltaway and 

 Mr. Wadmore. It is generally assumed by chemists at the 

 present time that in these substances the hydrogen is joined to 

 carbon and that they must be represented by such formula; as 

 II.CiN, HO.C:N, &c. The view that they are really the iso- 

 compounds of the formulas C;N.H, 0:C:N.H, &c., is again 

 brought forward by the authors, and the evidence afforded by 

 the behaviour of the haloid cyanogen compounds — which is that 

 of substances containing the haloid joined to nitrogen — is shown 

 to necessitate their representation by such imino-iofmuX-x. — A 

 modification of Zeisel's method for the estimation of methoxyl 

 groups, by Dr. J. T. Hewitt and Mr. T. S. Moore. The 



