446 



NATURE 



[March 9, 1893 



interest, but they at any rate show the rapability of this 

 method for the examination of subjects which would in the 

 ordinary way be considered beyond the reach of experi- 

 ment. It is hardly necessary to say. that the examples 

 given by no means reach the limit of what may be done, 

 I have examined the explosions produced by fifteen-grain 

 fulminate of mercury detonators and of heaps of iodide of 

 nitrogen, a material which is rather unmanageable, as if a 

 fly even walks over it it violently explodes. In these cases 

 the explosive flash was used to make the B gap of Fig. 4 

 conducting, for which it answered perfectly. One might 

 in the same way examine the form of the outrush of 

 powder gases past the bullet, and so find at once their 

 velocity with respect to the velocity of the bullet, and I see 

 no great difficulty in tracing, if this should be desired, the 

 whole course of a single bullet for perhaps as much as 

 100 yards by means of photographs taken every few 

 inches on its way. Though it may not be evident that 

 these or similar experiments are of any practical im- 

 portance, there can be no doubt that information may be 

 readily obtained by the aid of the spark photograph, as 

 in fact has been shown by Prof. Mach, Lord Rayleigh, 

 Mr. F. J. Smith, and others, which without its aid can 

 only be surmised, and that if, as in other subjects, the first 

 wish of the experimentalist is to see what he is doing, then 

 in these cases surely, where in general people would not 

 think of attempting to look with their natural eyes, it may 

 be worth while to take advantage of this electro- 

 photographic eye. 



I wish in conclusion to express my obligation to the 

 gentlemen to whom I have already referred, to Messrs. 

 Chapman and Colebrook for their assistance, and to 

 Messrs. Moore and Grey for having supplied me with 

 weapons and ammunition. 



A- 



MICRO-ORGANISMS AND THEIR 

 INVESTIGA TION> 



S ;the field of bacteriological investigation becomes 

 extended, we have of necessity constant additions 

 to the various methods rendering possible the pursuit of 

 researches in these novel directions. We have only to 

 look at the first edition of Hueppe's " Methoden der 

 Bakterien-Forschung," published in 1885, consisting of 

 174 pages, and compare it with the bulky volume of 

 488 pages which forms the fifth edition, to see at a glance 

 the advance which has been made in the matter of 

 methods alone. In Fliigge's "Die Mikro-organismen " 

 we have another type of book, dealing exclusively with 

 micro-organisms themselves, and the information which 

 has been gathered together concerning them, whilst all 

 details of bacteriological practice are purposely omitted. 

 Dr. Giinther has attempted a welding together of these 

 .two types of book, special attention being given to micro- 

 scopical technique with which his name is indeed more 

 particularly associated. 



The first part is devoted to a survey of our knowledge 

 concerning bacteria in general, commencing with the 

 earliest observations of Leeuwenhoek in 1683. In this 

 review we find an account of their morphology, the prin- 

 ciples upon which their classification is attempted, &c., 

 together with a detailed account of the most recent 

 methods for their cultivation and subsequent study, 

 including careful directions for the use of the microscope, 

 and a most elaborate description of the available means 

 for staining bacteria. 



The second part is confined to a consideration of 

 the best-known pathogenic and non-pathogenic micro- 

 organisms. 



There could not be a more admirable account of the 



1 " Einfuhrung in das Studium der Bakteriologie." By Dr. Carl 

 Giinther. Second Edition. (Leipzig : Georg Thieme.) 



" Technique Bact^riologique." By Dr. R. Wurtz. Encyclopedie Scien- 

 tifique des Aide-M^inoire. (Paris : Gauthier-Villars et fils, 1892.) 



numerous manipulations involved in bacteriological in- 

 vestigations ; all the minutiae are described with the 

 utmost care, and what is usually left for the student to 

 learn in "profiting by his experience" is here carefully 

 anticipated, and if he tumbles into any pitfalls, it is not 

 because he has been without warning. 



With such a big task as Dr. Giinther has set himself 

 it is not surprising to find some parts less amply dealt 

 with than they would seem to deserve. Thus we find 

 but a very meagre supply of culture media given, there 

 is no mention of the preparation of milk, or of the 

 special solutions employed by Pasteur, Naegeli, and 

 others, neither is there any account of Kiihne's silica 

 Jelly, which since our knowledge of the fact that certain 

 organisms will only flourish in media devoid of all 

 organic matter, ought surely to have been included. 



On the other hand a minute description is given of 

 gelatine-plate, dish and tube cultures, as well as of the 

 most modern methods for the anaerobic cultivation of 

 bacteria, &c. In connection with the abstraction of 

 certain colonies from gelatine-plates, mention may be 

 made of a piece of apparatus (the description of which 

 was only published after Dr. (jiinther's book appeared) 

 originally devised by Fodor, and called '' Bakterien- 

 Fischer," which has been, under the name of " Bak- 

 terienharpune," more recently modified and consider- 

 ably cheapened by Unna. Every one has experienced 

 the difficulty of fishing out a particular colony in a 

 crowded plate, how it is almost impossible to look 

 through the microscope and fix upon the centre to be 

 abstracted, and at the same time keep the needle steady 

 and ensure touching only the one colony which is re- 

 quired By u^ing the above contrivance, which can be 

 attached to the microscope, the fishing out of such 

 centres is greatly facilitated. 



The examination of air for micro-organisms is only 

 very slightly touched upon, as is also the bacteriological 

 investigation of water. It is a little rash to assert that 

 " pathogenic micro-organisms can live for a long time in 

 sterilised water," considering that it has been shown in 

 some cases that their immersion only is sufficient to 

 destroy them. Again, no mention is made of Hansen's 

 special methods for the examination of particular waters ; 

 although they are opposed to the Koch school, this 

 ought not to preclude a reference to what has been 

 proved by a large number of investigations to be, in 

 some cases, of great practical utility. 



The second part opens with a short introduction, in 

 which the nature of pathogenic organisms in general is 

 described, and an account given of the rigid proof which 

 is required before a particular organism may be said to 

 be the cause of a particular disease. Protective inocula- 

 tion and immunity are briefly referred to, and Metschni- 

 kofif's brilliant theories of phagocytosis summarily dis- 

 missed, and declared incapable of standing the test of 

 the "careful experimental criticism to which they have 

 been submitted by Fliigge, Baumgarten, and the author's 

 own pupils." 



As many as twenty-seven different varieties of micro- 

 organisms are described in the section on the most im- 

 portant pathogenic bacteria. Amongst these we find the 

 micro-organisms associated with anthrax, tuberculosis, 

 diphtheria, cholera, pneumonia, tetanus, typhoid fever, 

 and chicken-cholera, more especially dealt with, an ex- 

 ceedingly useful and comprehensive summary being 

 given in each case of what is known concerning them, 

 together with numerous references to original papers 

 published on the subject. That Dr. Giinther is an ardent 

 disciple of Koch's will at once be admitted, when we read 

 the terms in which he speaks of the Tuberculinum Kochii : 

 " Eine neue Aera begann nicht allein fiir die Tuber- 

 culoselehre, sondern fiir die gesammte Medicin, mit der 

 grossen Entdeckung Koch's der Heilung der Tuber- 

 culosa." 



NO. I 2 19, VOL. 47] 



