LITERARY NOTICES. 



129 



argument. The bacteria are classified at 

 once as " the lowest members of the vegeta- 

 ble kingdom, closely related to the algse." 

 Separate species are found among them, dif- 

 ferentiated by growth and shape. Accord- 

 ing to their forms they are divided into the 

 globular bacteria or micrococci, the rod- 

 shaped or bacilli, and the screw-like or spi- 

 rilla. Their structure, multiplication, con- 

 ditions necessary for growth, and resultant 

 phenomena are next considered. 



The benefits of oil immersion and of the 

 Abbe illuminating apparatus are unfolded in 

 Methods of Investigation, and the learner is 

 instructed in the handling of the microscope 

 and making of stains. Even the common 

 errors of beginners are outlined for the stu- 

 dent, and he is warned not to mistake the 

 broken nuclei of white blood-cells for ba- 

 cilli, when the glasses have been too hastily 

 pulled apart, or to fancy he has discovered a 

 colony of micrococci when some plasma-cells 

 betray idiosyncrasies in absorbing aniline 

 colors. 



Full directions are given for the various 

 processes involved in successful breeding, 

 sterilization, and the preparation of liquid 

 and solid food media. 



The noxious character of pathogenic bac- 

 teria is shown to consist not in the mechani- 

 cal effect of their presence, nor in the hospi- 

 tality they may exact from their host, but in 

 the alkaloidal poisons they generate. Fraen- 

 kel inclines to the belief that the organ- 

 ism resists through a germ-killing power 

 which resides in the living albumin of the 

 serum, and that victory over invading ba- 

 cilli is a chemical one and not the pitched 

 battle of the phagocytes. Some of the inter- 

 esting experiments of Metschnikoff in de- 

 fense of his theory are not quoted, but his 

 views are fairly represented. The author ad- 

 mits as pathogenic bacteria only those which 

 comply with three conditions : first, that they 

 are invariably present with the morbid affec- 

 tion ; second, that they can be cultivated 

 outside of the organism ; thirdly, when the 

 same pathological effects follow inoculation 

 of the artificial culture. Petri's method of 

 finding the number of bacteria in a given 

 quantity of air is preferred. Only three to 

 five germs in a litre is the average amount 

 computed for an ordinary dwelling. Bacte- 

 riological examination of the soil is compli- 



VOL. XLI. 12 



cated and of little use, but that of water is 

 extremely important, although the determi- 

 nation of species is difficult. " Water may 

 be harmless and contain five thousand germs 

 of the hay bacillus to the cubic centimetre, 

 but ten germs among which are two cholera 

 vibrios and two typhoid bacilli render it dan- 

 gerous." 



The principal mold and yeast fungi are 

 briefly noticed in the appendix. The book 

 is indexed, but lacks illustrations. Minute 

 descriptions atone for this ; however, the 

 student is expected to illustrate for himself 

 in the best way by observation of the liv- 

 ing object. 



The Electric Railway in Theory and Prac- 

 tice. By Oscar T. Crosby and Louis 

 Bell, Ph. D. New York : W. J. John- 

 ston Co., Limited. Pp. 400. Illustrated. 

 Price, $2.50. 



Although electric traction in the United 

 States only dates from 1884, its development 

 has been so rapid that for public transit in 

 towns and cities it would seem that the days 

 of the horse are numbered. Of electric loco- 

 motion as a science and art this book is a 

 clear and thorough presentation. Beginning 

 with an outline of electrical theory, the au- 

 thors proceed at once to practical details. 

 The considerations which should determine 

 the placing of a station are first discussed, 

 as also the economical adaptation of plant to 

 a specific volume of traffic and frequency of 

 service. Steam-engines and water-wheels of 

 the best models are described and their mer- 

 its carefully discriminated. Motors and car 

 equipment are then canvassed, and the vari- 

 ous approved methods of building lines and 

 track are illustrated. The trolley, under- 

 ground conduit, and storage-battery systems 

 are next compared, with a complete array of 

 evidence pro and con. 



Mr. Crosby, one of the authors, has con- 

 ducted the only series of experiments ever 

 undertaken with intent to double railroad 

 speeds. In one of the most interesting chap- 

 ters in the book he gives all the facts in the 

 case, with cautiously deduced estimates. His 

 conclusion is, that with electric motors of 

 the highest efficiency, there is an advantage 

 over the locomotive at all speeds. This ad- 

 vantage is fifteen per cent at twenty miles 

 an hour, and steadily increases as the rate 

 is quickened. Where motors are liable to a 



