234 



NATURE 



{July 19, 1877 



mention only incidentally as the present conference does 

 not deal with education in the ordinary sense of the word. 

 It will not be suspected that I wish to make physio- 

 logists of all the world. It would be as reasonable to 

 accuse an advocate of the " three R's " of a desire to make 

 an orator, an author, and a mathematician of everybody. 

 A stumbling reader, a pot-hook writer, and an arith- 

 metician who has not got beyond the rule of three, is not 

 a person of brilliant acquirements ; but the difference 

 between such a member of society and one who cannot 

 either read, write, or cipher is almost inexpressible ; and 

 no one nowadays doubts the value of instruction, even if 

 it goes no further. 



The saying that a little knowledge is a dangerous thing 

 is, to my mind, a very dangerous adage. If knowledge 

 is real and genuine, I do not believe that it is other than 

 a very valuable possession, However infinitesimal its 

 quantity may be. Indeed, if a little knowledge is 

 dangerous, where is the man who has so much as to be 

 out of danger .'' 



If William Harvey's life-long labours had revealed to 

 him a tenth part of what may be made sound and real 

 knowledge to our boys and girls — he would not only have 

 been what he was, the greatest physiologist of his age, 

 but he would have loomed upon the seventeenth century 

 as a sort of intellectual portent. Our little knowledge 

 would have. been to him a great, astounding, unlooked-for 

 vision of scientific truth. 



I reaUy see no harm which can come of giving our 

 children a little knowledge of physiology. But then, as I 

 have said, the instruction must be real, based upon ob- 

 servation, eked out by good explanatory diagrams and 

 models, and conveyed by a teacher whose knowledge has 

 been acquired by study of the facts, and not the mere 

 catechismal parrot-work which too often usurps the place 

 of elementary teaching. 



It is, I hope, unnecessary for me to give a formal 

 contradiction to the silly fiction, which is assiduously 

 circulated by fanatics who not only ought to know, but 

 do know, that their assertions are untrue, that I have 

 advocated the introduction of that experimental discipline 

 which is absolutely indispensable to the professed physio- 

 logist, into elementary teaching. 



But while 1 should object to any experimentation which 

 can justly be called painful, for the purpose of elementary 

 instruction, and while, as a member of a late Royal 

 Commission, I gladly did my best to prevent the infliction 

 of needless pain for any purpose, I think it is my duty 

 to take this opportunity of expressing my regret at a 

 condition of the law which permits a boy to troll for pike, 

 or set lines, with live frog bait, for idle amusement ; and, 

 at the same time, lays the teacher of that boy open to 

 the penalty of fine and imprisonment if he uses the same 

 animal for the purpose of e.xhibiting one of the most 

 beautiful and instructive of physiological spectacles, the 

 circulation in the web of the foot. No one could under- 

 take to affirm that a frog is not inconvenienced by being 

 wrapped up in a wet rag, and having his toes tied out ; 

 and it cannot be denied that inconvenience is a sort of 

 pain. But you must not inflict the least pain on a 

 vertebrated animal for scientific purposes (though you 

 may do a good deal in that way for gain or for sport) 

 without due licence of the Secretary of State for the 

 Home Department, granted under the authority of the 

 Vivisection Act. 



So it comes about, that in this present year of grace 

 1877, two persons may be charged with cruelty to animals. 

 One has impaled a frog, and suffered the creature to 

 writhe about in that condition for hours ; the other has 

 pained the animal no more than one of us would be 

 pained by tying strings round his fingers, and keeping 

 him in the position of a hydropathic patient. The first 

 offender says, " I did it because I find fishing very 

 amusing," and the magistrate bids him depart in jjeace ; 



nay, probably wishes him good sport. The second pleads, 

 " I wanted to impress a scientific truth, with a distinct- 

 ness attainable in no other way, on the minds of my 

 scholars," and the magistrate fines him five pounds. 



I cannot but think that this is an anomalous and not 

 wholly creditable state of things. 



OUR ASTRONOMICAL COLUMN 

 D'Arrest's Comet.— M. Leverrier notifies the dis- 

 covery of the periodical comet of D'Arrest by M. Coggia 

 at Marseilles, on the 8th inst., nearly in the position 

 assigned by M. Leveau's calculations. It was also 

 detected at Florence by M. Tempei, on the 10th. 



The comet was discovered by the late Prof. D'Arrest at 

 Leipsic on June 27, 1S51, and observed till October 6. 

 The elliptical character of the orbit was pointed out by 

 the discoverer early in August, and his conclusions were 

 verified by the calculations of Vogel and Villarceau 

 shortly afterwards, the latter astronomer commencing, 

 while the comet was yet under obsiivation, a series of 

 elaborate computations of the effect of planetary per- 

 turbations upon its motion, which were continued by him 

 until taken up by Leveau. With the aid of Villarceau's 

 ephemerides the comet was detected on its ensuing return 

 to perihelion at the Royal Observatory, Cape of Good 

 Hope, and observed from December 5, 1S57, to January 

 18, 1858. Oudemans, in a memoir published loy the Royal 

 Academy of Sciences at Amsterdam in 1854, had also 

 carried forward the elemenls to this appearance, his results 

 indicating that while the normal positions of 1851 were 

 best represented by a mean motion which would bring the 

 comet to perihelion again on December 5, 1S57, there yet 

 remained an uncertainty to the extent of eighty-five days 

 in the length of the revolution. Villarceau, in the Comptcs 

 Rcndus dc PAcadcmie dcs Sciences, 1852, December 6, 

 considered the period fixed within narrower limits, one of 

 his sets of elements assigning November 28, 1857, for the 

 next perihelion passage, on which day the Cape observa- 

 tions show that it actually occurred. At the second return 

 in the spring of 1864 the comet was not observed, and a 

 very heavy work was involved in the preparation of an 

 ephemeris for 1870, owing to the large pfenurbations due 

 to the action of Jupiter in 1861, the comet having in April 

 of that year approached the planet within 0-36 of the 

 mean distance of the earth from the sun, and the two 

 bodies remaining in proximity for a considerable time ; 

 it was therefore necessary to determine the effect of this 

 near approach to the most powerful of the planets with 

 every possible precision, a long work successfully accom- 

 plished by Leveau, who found on continuing the calcula- 

 tion of the perturbations of Jupiier, Saturn, and Mars, to 

 June, 1870, the following material changes in the elements 

 at the perihelion passage in November, 1857. 



Long, of Perihelion 



,, Ascend. Node 

 Inclination ... 



-432 

 + I 43 



Angle of Eccentricity - 1 52 

 Mean anomaly ... -|- 10 10 

 Mean motion ... — i;''82 



So that the period of re"olution was lengthened sixty- 

 eight days, the comet arriving at perihelion on September 

 22, 1870. The effect of these perturbations was to alter 

 the geocentric place at this time, no less than ii4°'6 m 

 right ascension, and 7° 6 in declination. At all three 

 returns the comet has been a faint object, and it was 

 particularly so in 1870, when it was, nevertlieless, 

 sufficiently observed. Prof. Julius Schmidt, profiting by 

 his fiivourable position at Athens, to follow it until nearly 

 the end of the year. 



The following are the dimensions of the orbit of 

 D'Arrest's comet in the present year, according to the 

 elements of Leveau. 



Semi-axis major ... 354139 I Perihelion distance 1-31809 



minor ... 275651 ApheHon „ ... S76469 



Semi-parameter ,,. 2-14559 | Eccentricity ■. 0-627SU4S 



