December 25, 1902 J 



NA TURE 



189 



to the importance of nature-study as a factor in the new educa- 

 tion, the author insists on its value as a means of cultivating the 

 powers of observation and at the same time warns his readers 

 that it is not to be considered as in any way identical with 

 elementary science. Various definitions and limitations of the 

 subject are then given, after which attention is directed to its 

 aims and objects. Among these, stress is laid on its power of 

 interesting pupils — especially those to whom the ordinary school- 

 curriculum is peculiarly distasteful — and thus rendering educa- 

 tion a pleasure rather than a toil. It is also urged that nature- 

 study promises to be the form of education best adapted to 

 develop the pupils into good citizens capable of making their 

 way in the world and, above all, of relying on their own judg- 

 ment. Healthful it certainly is, and the love of nature it en- 

 genders may, it is suggested, tend to check the exodus of the 

 population from the country to the towns. The difficulty of 

 securing the right class of teachers claims a considerable share of 

 attention, and some amount of discussion is devoted to the 

 question as to the extent to which books should be used. Col- 

 lecting, again, is a phase of the subject which requires very 

 careful treatment in order to prevent the pupils from degenerat- 

 ing into mere curiosity-hunters. The author is, however, of 

 opinion that both books and collections have their place in 

 the scheme. The relative values of outdoor and indoor work 

 are then discussed, in the course of which much importance is 

 attached to the "seasonal method" of study. Before the final 

 summary, the article winds up with observations on teachers of 

 all grades and classes, and the best method of training them, 

 followed by a reference to the objections against, and the diffi- 

 culties connected with, " nature-study." 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, November 27. — "The Inter-relationship of 

 Variola and Vaccinia." By S. Monckton Copeman, M. A. , M. D. 

 Cantab., F.R.C.P. Communicated by Lord Lister, F.R.S. 



The term "variola vaccinae" employed by Jenner, as a 

 synonym for cow-pox, has been generally accepted as affording 

 evidence that, in so naming this disease "small-pox of the 

 cow," he was desirous of placing on record his belief that cow- 

 pox or vaccinia was intimately related to human small-pox, if 

 indeed it were not directly derived from it. 



But the difficulty experienced by the writer and numerous 

 other investigators in attempts to transmit small-pox to bovines, 

 whether cows or calves, has not infrequently been cited as a 

 reason for regarding Jenner's theory with distrust. 



It is well known, however, that a great deal, at any rate, of the 

 small-pox which was prevalent at the time that Jenner lived and 

 wrote was of that comparatively mild variety which, under the 

 name of inoculated small-pox, was intentionally produced in 

 healthy subjects, with the object of thereby conferring protec- 

 tion against subsequent attack by the disease in virulent 

 form. 



So mild indeed, at times, were the results of inoculations in 

 the hands of such operators as Adams and the brothers Sutton, 

 that, as we learn from contemporary records, in many instances 

 but little obvious effect was observed, with the exception of the 

 local vesicle arising at the site of insertion of the small-pox 

 virus. The majority of persons thus inoculated are not likely, 

 therefore, to have been incapacitated, as the result of the opera- 

 tion, to a much greater extent than are those who undergo 

 efficient vaccination at the present day, and, doubtless, they 

 would be, for the most part, capable of following their ordinary 

 avocations during the progress of the induced disorder. 



Not only were the effects following on inoculation compara- 

 tively mild, but the disease in this form was intentionally 

 carried into many country districts which otherwise might not 

 have become invaded by small-pox. 



In the light of these facts, it would appear not improbable 

 that it was from the inoculated form of small-pox rather than 

 from the ordinary variety of the malady that much, at any rate, 

 of thecow-pox in]the pre-vaccination era was derived. Suppos- 

 ing this to have been the case, it is not difficult to understand 

 how that the cracks, so often found on the udders of cows, might 

 become infected by a milker with fingers contaminated by 

 contact with the inoculation sore upon his arm. 



In default of inoculated small-pox in the human subject, use 

 was made of the monkey, which, as the writer had shown in 



NO. I/30, VOL. 67] 



a previous communication to the Royal Society, is readily 

 susceptible to the disease. The necessary small-pox material 

 has been obtained during the course of recent outbreaks of 

 small-pox at Middlesbrough, Glasgow and London. 



The results of the experiments may be briefly summarised as 

 follows : — In each of the separate series, the human small-pox 

 lymph or pulp was first inoculated directly on calves, and in 

 every instance, so far as could be observed, with altogether 

 negative results. But with monkeys, success was as invariably 

 obtained, and when, after one or more passages through this 

 animal, the contents of the local inoculation vesicles were em- 

 ployed for insertion on the calf, an effect was now produced 

 which, after two or three removes in that animal, was indis- 

 tinguishable from typical vaccinia. Moreover, from the con- 

 tends of vesicles raised in this manner on the calf, a number of 

 children have been vaccinated, some of whom were afterwards 

 kept under observation for a considerable period. Every such 

 vaccination "took" normally, and in no case was any bad 

 result subsequently observed. 



The experimental results obtained all tend, then, to confirm 

 the view that the vaccinia of Jenner's time was derived, in all 

 probability, from a comparatively mild form of small-pox. Of 

 even more importance is the fact that the work has afforded 

 conclusive evidence of the essential identity of the virus of 

 smallpox and cow-pox or vaccinia. 



December 4. — "On the Vibrations and Stability of a 

 Gravitating Planet " By J. H. Jeans, B.A., Isaac Newton 

 Student and Fellow of Trinity College, Cambridge. Com- 

 municated by Prof. G. H. Darwin, F.R.S. 



The first part of the paper deals with the vibrations and 

 stability of a gravitating elastic sphere. The matter is not 

 necessarily homogeneous, but is arranged in spherical layers. It 

 is pointed out that, in the classical investigation of the displace- 

 ments produced in a gravitating sphere by given surface-forces, 

 the most important of the gravitational terms is omitted. The 

 effect of this omission is to necessitate a correction, and this may 

 entirely invalidate the solution when we are dealing with spheres 

 of the size of the earth or other planets. In fact, it appears that 

 for a gravitating solid of the kind we are discussing the spherical 

 configuration may be one of unstable equilibrium, the instability 

 being brought about by these gravitational terms. The vibration 

 through which instability first enters is one in which the 

 displacement at every point is proportional to a harmonic of the 

 first order. 



In a former paper, " The Stability of a Spherical Nebula" 

 (Phil. Trans., A, vol. cxcix., p. 1), the suggestion was put 

 forward that the instability of a nebula, sun or planet, which, 

 upon the nebular hypothesis, is supposed ultimately to result in 

 the ejection of a satellite, may be largely brought about by a 

 gravitational tendency to instability of the kind described. We 

 take, for the moment, an extreme hypothesis, and imagine that 

 this agency is the preponderating agency and that the rotational 

 tendency to instability may be disregarded in comparison. 



Except for the changes which have occurred since the con- 

 solidation of the planets, the solar system supplies material for 

 testing the consequences of this hypothesis. When a number of 

 planets of varying masses have thrown off satellites, we find 

 (upon our present extreme hypothesis) that the masses ought to 

 be proportional to the squares of the radii. It is found that this 

 law is approximately obeyed in the solar system. It is further 

 found that the absolute values of the masses and radii are 

 approximately such as would be expected. 



It is interesting to compare two extreme hypotheses, the first 

 referring the phenomena of planetary evolution solely to 

 rotational, the second solely to gravitational, instability. Given 

 the approximate values of the density and elasticity of a planet, 

 and the fact that this planet has thrown off a satellite, then the 

 former hypothesis leads to a certain inference as to the angular 

 momentum of the system, the latter to an inference as to the 

 radius of the primary. The former leads to no inference at all 

 as to the size of planets which are 10 be expected — they are as 

 likely to be of the size of billiard balls as of the size of the 

 planets of our system — while the latter leads to no inference as 

 to the angular momentum of the system, but presupposes it to 

 be small. The contention of the present paper is that the 

 inferences which are drawn from the former hypothesis are not 

 borne out by observation on the planets of our system, while 

 those which are drawn from the latter are borne out as closely 

 as could be expected. The true hypothesis must of necessity 

 lie somewhere between the two extremes which are being 



