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THE AMERICAN NATURALIST [Vol. XL 



lications." Not only is it necessary to determine motility, but the 

 organs of motility should be stained. The part of the work dealing 

 whh culture media is an excellent treatise; every working bacteriol- 

 ogist can get many valuable suggestions from it. The many con- 

 flicting statements as to the behavior of organisms by different authors 

 arise largely from the character of the media used. In regard to 

 vegetable media, he prefers to have them sterilized in the steamer rather 

 than the autoclave. If boiling changes the nature of any fluids it 

 is advisable to use the Chamberland or Berkefeld filter, but Chamber- 

 land bougies should not be used continuously for more than three 

 days, because of the growth of small organisms in the walls of the 

 fiker, when they should be sterilized. There is a highly interesting 

 discussion of sensitiveness to plant acids. The Bacillus tracheiphilus 

 is used to show tolerance for sodium hydrate. Its tolerance for 

 this substance can be considerably increased by inoculating each 

 time from alkaline bouillons rather than from acid ones. The 

 thermal relations of bacteria are among the most interesting and 

 should be studied with great care. Under the head of economic 

 aspects of the subject he argues with force that more attention 

 should be given to the collection of accurate statistics by competent 



excellent suggestions on natural nu^tliods of inl'cction, how the para- 

 ported from one field to another carelessly; the parasite may gain 

 an entrance through wounds, by way of the stomata, lenticels, water 

 pores, and nectaries. The keeping of records is an important part 

 of the work of the experimenter, and it would l)e well for every 

 bacteriologist to have Dr. Smith's work at hand and follow care- 

 fully the outlines given. The beginner should also be interested in 

 the card-catalogue system used by the author. 



like iiarillu.^ roli-romman i,s are to be regarded as - nnmimi r.rrhulrndar 

 We agree also that all species antedating the Koch poured-plate 

 method, which are not accurately described, should be abandoned. 



