Nov. 6, 1884] 



NA TURE 



instructions and advice as to methods of study are invalu- 

 able, and his opinions on the numerous debatable ques- 

 tions connected with micro-organisms entitled to the 

 highest respect. Dr. Klein has descended, as it were, 

 from his position of experimentalist and observer, in 

 order to place before the scientific public in a compact 

 form a r&sumi of what is known at this moment concern- 

 ing disease-producing micro-organisms. He classifies 

 these organisms as Micrococci, Bacteria, Bacilli, Vibriones, 

 Spirobacteria, Yeast-fungi, and Mould-fungi, and gives 

 seriatim under each head, accompanied by numerous 

 figures, often original, an account of such forms as have 

 been found in association with disease. He refers the 

 reader to the original writings in which this or that 

 organism has been described, and whilst he sometimes 

 judiciously throws doubt on a claim to pathogenic powers, 

 he is entirely relieved from the responsibility of a critic 

 in all cases by the disclaimer in his preface and by the 

 fact that he obviously intends to leave the question in 

 most cases to further inquiry. As an illustrated cata- 

 logue of reputed pathogenic Schizophytes, with references 

 to original authorities, the work is invaluable. 



At the same time Dr. Klein does, as so ripe a student 

 of these questions must, commit [himself to very definite 

 opinions on some of the great problems of what it is con- 

 venient to term " Bacteriology." Dr. Klein clings to the 

 belief that speaking broadly the forms known as Micro- 

 cocci, Bacteria, Bacilli, Vibriones, and Spirilla breed true 

 and are to be recognised as true genera. This opinion is 

 traceable to the fact that his studies have been chiefly 

 (like those of Koch, who holds a similar view) carried out 

 on parasitic {i.e. pathogenic) Schizophytes. And it is 

 highly probable that it is more difficult (in some cases 

 impossible) to break down the specific form by change of 

 environment of a parasitic Schizophyte than of free-living 

 kinds. But Dr. Klein has himself shown (p. 109) that Bacillus 

 (/>. anthracis] when cultivated in a certain way becomes 

 Micrococcus (torula-form), and other similar instances are 

 to be found in his book. Had he dealt with free-living 

 Schizophytes as well as parasitic ones, he would have 

 found ample evidence of the transformation, in the course 

 of growth and division, of Micrococci into Bacteria, of 

 these into Bacilli, and of these into Vibriones and Spirilla, 

 and of each of these directly or indirectly into the other 

 forms. The instability of the forms presented by par- 

 ticular kinds of Bacteria does not however imply, as has 

 been assumed by some writers (Billroth e.g.), that there 

 is only one " species " of Schizophyte. Such use of terms 

 would lead to the statement that there is only one " spe- 

 cies" of organism in all creation. The instability of the 

 forms of Schizophytes merely implies that the range of 

 presently observable specific characters taken as a whole 

 (which forms the true limits of what mankind at the 

 moment calls a " species ") is not simply and directly 

 coincident with the range of one particular and readily 

 observed set of characters, namely, those of form. A 

 great deal more depends upon the question of transmuta- 

 bility of the forms of Schizophytes than is admitted, at 

 present, by pathologists. We would merely warn them 

 that the doctrine of fixity of the forms of pathogenic 

 Schizophytes is as much an assumption and as much to 

 be received with caution as is the contrary doctrine of 

 the universal transmutability of such forms. One great 



fact is certain, viz. that some Schizophytes do exhibit the 

 positive evidence of change of form in the course of 

 growth under varying conditions. 



Dr. Klein has a most interesting chapter on the conver- 

 sion of innocuous into pathogenic organisms and vice 

 versd, in whjfh he criticises with great ability the results 

 of Buchner and Nageli on the one hand, and of Pasteur 

 on the other. Valuable as such critical dissertations are, 

 Dr. Klein will agree with us in thinking his experiments of 

 greatervalue. We shouldjbe'sorry were the test-experiments 

 which they suggest to be delayed in consequence of the 

 apparently satisfactory character of the reasonings which 

 he and others have very properly adduced. The fact is 

 that the proportion of what we know by careful experiment 

 and observation in reference to Bacteria and their allies — 

 as compared with what we must soon know and can see 

 how to know if only time and ability are directed to the 

 research — is so small that conclusions and generalisations 

 are not useful except as suggestions to those who are in 

 the thick of the "work. More experiment, more trial of 

 every conceivable condition of growth and nutrition, 

 applied to every kind of Schizophyte observed and yet to 

 be discovered, is imperatively called for. 



Who can say that much is known as yet about these 

 organisms, when even so earnest a student of them as Dr. 

 Robert Koch did not know that his so-called " cholera 

 comma-Bacillus" occurs in the mouths of nearly every 

 healthy man, woman, and child ? 



Dr. Klein has rendered a generous service to future 

 students of Bacteria by the publication of this little book. 

 The woodcuts are very abundant, and sufficient to give an 

 idea of the forms as they appear when stained by coloured 

 reagents. The botanical and chemical aspects of the 

 Schizophytes are necessarily not dealt with in this 

 treatise. E. Ray Lankester 



OUR BOOK SHELF 



A New Method of treating Glaucoma, based on recent 

 researches into its Patliology. By Geo. Lindsav 

 Johnson, M.A., M.B., B.C. Cantab. (H. K. Lewis, 

 1SS4.) 

 This little brochure is written by a Cambridge graduate 

 who has devoted considerable time and attention to the 

 study of diseases of the eye, and who has devised a new 

 and very serviceable form of ophthalmoscope. The pro- 

 position he endeavours to establish is " that the ordinary 

 method of treatment for glaucoma by iridectomy, though 

 highly successful in acute forms of the disease, is never- 

 theless both uncertain and unsatisfactory in the chronic 

 condition of glaucoma." The truth of this proposition all 

 those who have had large experience in the performance 

 of operations on the eye will freely admit : the reason is 

 less easy to give. Dr. Johnson describes the lymphatic 

 system of the eye, and adduces evidence to show that the 

 aqueous humour is secreted by the ciliary processes and 

 posterior surface of the iris, whilst it is drained off by the 

 canal of Fontana, and the meshwork at the corneo-iridal 

 angle. Any circumstance obliterating this angle is apt to 

 induce glaucoma. It is certainly not due to swellings of 

 the lens, since Brailey has shown that the lens is smaller in 

 the glaucomatous than in the normal eye, but Dr. Johnson 

 thinks that acute glaucoma may be referred to swelling and 

 inflammation of the ciliary processes, whilst in chronic 

 glaucoma there are slow and gradual changes in the 

 ciliary body and in the lejjfus around the angle of the 

 anterior chamber, whichgBhis opinion explains the 



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