490 Ihe American Naturalist. [June, 



pulling the fertilized flower down through the water without turning it 

 around. If I am correct in the observation that some plants of Yalli- 

 sneria have the dextral twist at the lower part, and others have the 

 sinistra] twist below, this would be a complex of the primitive anti- 

 dromy having superposed upon it a recently acquired didromy. 



A different line of investigation will search out the relation of dex- 

 trorse or sinistrorse phyllotaxy to the leaf-traces in the stem. I am con- 

 vinced that inattention to this point has marred some of the work on the 

 histology and the plan of the fibrovascular bundles, and that even with 

 opposite-leaved plants, many species will be found to exhibit a dupli- 

 cate pattern as between the arrangements in different individuals of a 

 species. — George Macloskie. 



Princeton College, March 16, 1896. 



VEGETABLE PHYSIOLOGY. 1 



A New Classification of Bacteria.— In a recent number of 

 Die Naturlichen Pflanzenfamilien (Lieferung 129, Leipsic, 1896) Prof. 

 W. Migula, of Karlsruhe, gives a classification of the bacteria which is 

 much more practical and satisfactory than that of Dr. Alfred Fischer, 

 noticed in the September (1895) number of this journal. Migula's ar- 

 rangement seems, on the whole, to be the best yet devised, and will 

 probably come into general use, at least among botanists. The charac- 

 ters of several genera are amended, properly it seems to the writer, 

 e. g., Bacterium, Bacillus, Streptothrix, and other genera are discarded 

 as being founded on purely biological grounds, e. g., Photobacterium, 

 Nitromonas, Clostridium. Of course, biological peculiarities are recog- 

 nized as indispensable in the differentiation of species. In reading this 

 paper one is occasionally surprised at the omissions, but taken in its 

 entirety the work of consulting literature seems to have been very care- 

 fully done, and what is more important the classification appears to 

 have grown out of a long and wide experience in the laboratory, and 

 seems to be eminently usable. This paper treats briefly of most important 

 literature, morphology, vegetative condition, resting state, cultures on 

 artificial media, biological peculiarities, geographical distribution, rela- 



^his department is edited by Erwin F. Smith, Department of Agriculture, 

 Washington, D. C 



