Oct. 17, 1872] 



NATURE 



491 



niimbsr and implied outlay. But it is a fact — for which 

 we can most positively vouch — that the good work done 

 at the present time in England with the microscope has 

 fallen very far behind its original proportion to the num- 

 ber of instruments in use. In fact we have in the history 

 of English research with the microscope, a typical case of 

 the breaking down of dilettantism. Nearly all the dis- 

 coveries easy tohand,whichcould be madebyhalf-an-hour's 

 pleasant peeping through a good microscope have been 

 made, and the numerous observers formerly urged on by 

 success have now become reduced to mere collectors of dia- 

 tom;and mounters of fleas. Ontheotherhand,inGermany, 

 an efficient microscope was produced somewhat later th.an 

 in this country, on a different system and at a far less cost. 

 It was not taken up by men of leisure and means, nor 

 were the makers tempted to produce the most elaborate 

 and costly mechanical contrivances for no practical end 

 but their own profit. The microscope in Germany fell 

 iiito the hands of the professed students of science in the 

 universities, and in consequence the art of applying this 

 instrument to the study of structure has steadily advanced 

 ia that country, until not only are all the important obser- 

 vations which are made with the microscope made in Ger- 

 man laboratories, or by those who have studied in them; 

 but the whole art or " technic " of microscopy has become 

 a German one. When we find that it is necessarj', for some 

 purposes, to watch a single cell for twelve hours or more 

 consecutively, and that three or four months' daily labour 

 is not considered too much to devote to advancing one 

 small step in the knowledge of such a matter as the nerve 

 branches which go to the glands in a frog's tongue, we 

 are not surprised that the dileltaiiti are no longer of ser- 

 vice in the progress of researches with the microscope. 

 Thorough and single-purposed men are required for such 

 v.-ork ; in short, " men of science," supported by special 

 institutions. 



It is then with very mixed feelings that we contemplate 

 Mr. Martin's book on Microscopic Mounting. It is of 

 about as much use for scientific purposes as would be an 

 alchemist's guide-book in a modern chemical laboratory. 

 Foreigners who do not know of the immense number of 

 microscopes annually sold in this country as toys, will 

 wonder who on earth can make any use of it. Microscopic 

 mounting is a proceeding which bears about the same re- 

 lation to the genuine microscopic study of an organism, as 

 enclosing a "subject "in its coffin does to human ana- 

 tomy. The object which is aimed at by the modern stu- 

 dent of histology is not to "mount" a pretty specimen, but 

 to apply such staining, clarifying, coagulating reagents, 

 and such methods of disruption, slicing, ' hardening, or 

 softening, as will enable him to discriminate, describe, 

 and draw structure ; or, it may be, so to arrange 

 the somewhat restrictive conditions of microscopical ex- 

 amination as may enable him to observe with the highest 

 powers the tissues of organisms in their liviin; state. He 

 does not care a dump for " mounting," and if he has in 

 the course of his work prepared some hundred or two 

 preparations of an o.'gan or organism which he is inves- 

 tigating, the preparations are usually thrown away when 

 the problem under investigation is solved, or lie for years 

 undisturbed in the catacombs of some cabinet. Mr. 

 Martin is of no assistance whatever in all that relates to 

 the use of reagents or adjuncts to observation with the 



microscope. He is evidently quite ignorant of German ; 

 he gives a nmnber of receipts taken from a variety of 

 antiquated English sources ; others be takes without 

 acknowledgment from the " Quarterly Journal of Mi- 

 croscopical Science ;'' see, for example, the paragraph on 

 staining tissues, p. 144, which can only serve to misleail. 

 Some, of course, amongst Mr. Martin's instructions arc 

 correct ; but we feci convinced that he has not made trial 

 of even the few methods which he has imperfectly de- 

 scribed ; and we decidedly object to his assuming the 

 office of a guide, when it is but a case of the blind lead- 

 ing the blind. 



Still, Mr. Martin's book may be looked at as an in- 

 teresting specimen of the phase which EngUsh dih-ttaiitc 

 microscopy has now reached. Had the author been a 

 little more careful in confining himself to what he really 

 understood as a dihgent mounter of microscopic objects, 

 his volume would have had a genuine antiquarian interest, 

 and would have perhaps been useful ; indeed, it mnv even 

 now in some ways be so to those who take a view of the 

 microscope similar to his own. 



It would hardly have been worth while expending so 

 many words on a book in itself of so little significance, 

 had not there been two conditions in existence which, if 

 passed by without remark, may have some consequences 

 which had better be avoided. Firstly, the number of per- 

 sons, medical students and others, now entering on the 

 serious study of histology, and the use of the microscope 

 as an instrument of scientific research, is increasing. 

 They want books to supplement the efforts of teachers in 

 putting them into the way of working and explaining to 

 them — if we may so say— the most useful " dodges.' 

 Secondly, there are other books besides Mr. Martin's 

 which profess to give instruction on microscopic manipu- 

 lation, and are all woi-thlcss. The students may, in 

 their innocence, be led to purchase such books. We wish 

 them to avoid making this mistake. There is no satis- 

 factory book in English on the subject. Beale's is the 

 best, but too large, and not sufficiently complete excepting 

 as to his own methods. Frey'sbook, which exists in bo h 

 a French and a German form, is the best foreign guide to 

 microscopic Tccliiiik. 



OUR BOOK SHELF 



Magiiclism and Deviation of the Compass. For the use of 

 Students in Navigation and Science Schools. By 

 John Merrifield, LL.D., F.R.A.S. (Lor.don : Long- 

 mans and Co.) 

 The Admiralty Manual of Compass Deviation with its 

 auxiliary Elemenatry Manual would, after some lap^e of 

 time, appear to have been turned to good account by 

 teachers of navigation. The small volume under re\ie\v 

 is one of a plentiful supply which appears to be now 

 issuing from the press on a subject of vast importance 1 1 

 seamen of the present generation ; and as such is 

 deserving of notice. 



It contains useful information of an elemental y kirie', 

 although this information is not presented either in the 

 practical form or exact and mathematical arrangement i f 

 the two manuals we have noticed as the fountain heads of 

 the science of magnetism as applied to iron ships and 

 their compasses. 



It is to be regretted that in a subject where clearness 

 and precision are essentials to teaching. Dr. Merrifield 



