ZOOLOGY AND BOTANY, MICROSCOPV, ETC. 433 



which the dental hygiene has been neglected, in the cheesy matter 

 covering the teeth. In the case of well-cared-for mouths amoebae are 

 found in about 50 p.c. of the examinations, and generally speaking their 

 presence coincides with a lowering of the normal resistance of the 

 subject, and may therefore be considered as a predisposing cause of 

 PyorrJuca. Amcebse are invariably absent in the various acute infec- 

 tions of the buccal cavity, while their presence is frequent in states of 

 chronic infection. The rational hygiene of the buccal cavity consti- 

 tutes the best means in completely excluding amoebae or at least 

 considerably reducing their numbers. The use of hydrochlorate of 

 emetine, so highly spoken of by other observers, has, in the author's 

 hands, been barren of results. 



"Aids to Bacteriology."* — This may be recommended to the 

 student as a useful book of reference, both as regards technique and the 

 theoretical aspects of the subject. The earlier chapters are devoted to 

 a description of bacteriological apparatus, the preparation and use of 

 nutrient media, and the technique of the preparation of material for 

 microscopical examination. The nine following chapters contain 

 descriptions of all the ordinary pathogenic bacteria in relation to their 

 pathogenicity, cultural reactions, morphology, and methods of differen- 

 tiation. The chapters are divided into the acid-fast organisms 

 {B. tuberculosis, B. lepra, etc.) ; spore-bearing pathogenic organisms 

 {B. tetani, B. adematis maligni, B. serogenes capsidatis, etc.) ; the 

 colon-typhoid group {B. coli, D. typhosus, B. paratyphosiis A. and B., 

 B. dysenteriae, etc.) ; the Badllus diphtherise group ; the Imcilli of 

 the hfemorrhagic septicaemias {B. pestis, B. pseudo-tuberculosis roden- 

 tium, etc.) ; micro-organisms of suppuration and septic diseases (staphy- 

 lococci, streptococci, pathogenic tetvacocci, B.pyocyaneus, the gonococcuo, 

 the meningococcus, the acne bacillus, and Diplococcus rheumaticus). 

 Chapter IX. discusses the pneumococcus and Micrococcus melitensis (no 

 mention is made of 31. 2}aramelitensis), and Chapter XII. the influenza 

 bacillus, Ducrey's and the Kocks-AVeeks Bacillus, tlie bacillus of whooping- 

 cough (Bordet and Congou), the glanders bacillus, and the bacillus of 

 epidemic abortion in cattle. Chapter XIII. is devoted to the cholera 

 vibrio and cholera-like vibrios. The next six chapters cover a very 

 wide range of subjects in a somewhat discursive manner, the tricho- 

 mycetes, the blastomycetes, the hyphomycetes, pathogenic protozoa, 

 enzymes, sulphur and iron bacteria, bacterial diseases of plants, diseases 

 of questionable origin, and the filterable viruses being briefly surveyed. 

 The last three chapters are devoted to the bacteriology of sewage, 

 shellfish, soil, air and milk, the bacteriology of water, and the chemistry 

 and application of disinfectants. The book concludes with a small 

 appendix and a copious and useful index. 



* Aids to Bacteriology, by C. G. Moor, M.A. (Cantab.) F.I.C., and William 

 Partridge, F.I.C., 3rd ed. 



