April 27, 1883.] 



KNOWLEDGE 



245 



tliat in every community tliere exist persons capable of 

 inventing absolutely baseless charges. So that many are 

 ready to pass over in silence anonymous attacks against 

 themselves or their friends, rather than sutler in character 

 during attempts which may fail to detect the scoundrel 

 who is in their midst, but as yet unknown to them. 



It were well if all men had the courage to despise this 

 risk. It should be regarded as so sacred a duty to expose 

 miscreants of the kind we are dealing with, that all ques- 

 tion of personal feeling should be set on one side. And, 

 after all, very little real harm can be done even l>y the 

 widest possible publication of anonymous charges, for only 

 very foolish persons can possibly attach the least weight to 

 them. Besides (though this is not a very lofty considera- 

 tion), they spread widely enough even when men are most 

 careful to keep them close, and it is better they should be 

 published by those attacked, than secretly spread by those 

 who originated them. A'ery often the only chance of 

 detecting the hidden villain is by making his charges so 

 widely public that some will hear of them who may have 

 means of knowing whence they sprang. 



These considerations have been partly suggested to my 

 mind by the recent receipt of an anonymous post-card, of 

 an abusive kind, which I received through the publisher of 

 Knowledce, to whom it had been sent, marked in such a 

 way as to attract, and even force, attention. The writing 

 of even signed abuse on a post-card is an offence of the 

 dynamitic type, because no one can tell by whom such a 

 card may be seen, or who may be hurt by it. But even in 

 these depths there is a deeper still, and worse than the 

 ordinary anonymous letter-writer, villain though lie is — 

 worse than one who signs his name to post-card abuse, 

 ruffian though Ilc must be — is the creature who issues 

 anonymous abuse on post-cards for all to read through 

 whose hands the card must pass. 



The case in point illustrates the certain evil which every 

 anonymous letter must produce. Though at first I had no 

 doubt that the communication came from the one person 

 who ought to have known about the matter (sixteen 

 months old) chiefly touched on by the writer, I think it 

 now quite likely that I may have been mistaken. I do 

 not know, may be I shall never know ; and I am not very 

 greatly concerned to correct the mistake, if such there be, 

 till I do know ; for undoubtedly the rascality of the post- 

 card writer would have been impossible but for mistaken 

 and self-injuring suspicion on the part of the only person 

 who could have given him his information, true up to a 

 certain point, and beyond that based entirely on an 

 unworthy suspicion. But, putting this person on one side, 

 the range over which my doubts might extend is wide 

 enough. To any acquaintance of his who chanced to 

 have some grudge against me (and no one who has 

 been as much before the public as I have for the 

 last fifteen j'ears or so can be witliout enemies, if he is 

 honest) the suspicion might attach, that he had been guilty 

 of one of the most contemptible of the petty villanies of 

 social life. Yet there are some clues by which Mr. 

 Lockyer, who is the person chiefly concerned, may, if he 

 please, help to detect the wrong-doer. He may rest assured 

 that, if he is really anxious to sift this matter to the bottom, 

 I will help him — publicly, not privately ^to the utmost of 

 my power. He knows, and I do not, to whom he has con- 

 fided recently (it must be recently, for no one would keep 

 snch a matter many d^iys in his mind) the terrible fact that 

 nearly seventeen months ago I replied, under " Answers to 

 Correspondents," to a letter addressed to me as Editor of 

 Knowledge (in which character I had addressed him) about 

 a paper which I had invited him to write. He knows who, 

 among his friends, would rejoice in imagining that this 



might be a means of annoying, and even injuring, me. He 

 may be able to guess who, among his fricuils, is capable of 

 writing an abusive, unsigned note on a postcard, sent to a 

 public ofllce. I think I can supplj- such additional infor- 

 mation as may perchance enable him to select among those 

 wlio answer this di scription (and surely he cannot know 

 many such scoundrels) the particular scoundrel who did 

 this thing. If evidence from writing will be of any use — 

 and even a print hand may reveal the writer — I wUl pub- 

 lish a facsimile (by photographic means) of enough of the 

 Utter to indicate its character and to serve this purpose. 

 I may do this in any case, as 1 have thought it my duty, 

 in any case, to indicate my recent doubts as to the author- 

 ship of the communication. 



The matter is utterly trifling, and beneath notice as re- 

 gards myself ; but as the detection of even the paltriest of 

 the villains who attempt to do mischief by explosives is 

 important, even when they have done no harm, and are 

 really powerless to do any, so I hold it to be of great im- 

 portance that those in our midst who are ready to tamper 

 with social dynamite should be detected and exposed. As 

 I am earnest in wishing this, and Mr. Lockyer has abun- 

 dant reason for desiring it, I have little doubt that, should 

 he, being innocent, assist to the utmost of his power, we 

 shall succeed in unearthing the real wrongdoers. 



PLEASANT HOURS WITH THE 

 MICROSCOPE. 



By Hexry J. Slack, F.G.S., F.RM.S. 



THE aphides found in swarms at this time of the year 

 in greenhouses will be viviparous females, as men- 

 tioned in the last paper. Females of this description 

 produce numbers of young, by an internal process which 

 has been likened to the budding of plants, and they may, 

 perhaps, be well compared with the infant bulbils pro- 

 duced so freely in that well-known garden flower, liliuin 

 bulbiferum. Females which lay eggs are distinct from the 

 viviparous sort, and Mr. Buckton states that in the aphis 

 tribe the former are always wingless, though winged in 

 some other groups. The viviparous females, at certain 

 times, give birth to young ones (ji7i//(f), which develop 

 wings to assist their migration, but they are not strong 

 fliers, and drift easily with the wind. The appearance of 

 males is rare in some species, and in all, the great swarms 

 result from the action of the viviparous females. In many 

 cases, the egg-laying must conduce to the maintenance of 

 the species, as the eggs require no external supply of food, 

 but the insect, as well as the egg, can withstand a con- 

 siderable amount of winter cold. 



If the reader has caught and watched some aphides, as 

 advised in the last paper, their rapid multiplication will be 

 understood. Various calculations have been made as to 

 the astounding quantities and the prodigious bulk and 

 weight that would be attained if no check occurred to 

 lessen the fertility. " A Mathematical Friend " cited by 

 Mr. Buckton improved upon Professor Huxley's calcula- 

 tion ; and, on the supposition that one aphis would pro- 

 duce twenty young ones in as many days, and each one of 

 these would begin, when five days old, to rear a family of 

 the same size, and so on in succession, found that at the 

 end of three hundred days the descendants of the original 

 ancestress would amount " to the fifteenth power of 210, 

 which it is almost impossible to express in figures. There 

 would be room for nothing else in the world but aphides." 

 Similar calculations might be made with reference to many 



