618 



SCIENCE 



[N. 8. Vol. XLI. No. 1060 



believes that the feeding power of plants is 

 satisfactorily explained, without the interven- 

 tion of other acids than carbonic. Since the 

 failure to establish that plants excrete notable 

 amounts of other acids than carbonic, some 

 investigators, as previously stated, have sug- 

 gested that the differences in feeding power 

 may be due to differences in amount of carbon 

 dioxide excreted. A careful consideration of 

 available data lends little support to this 

 idea. It seems rather that it is the efficiency 

 with which the carbon dioxide is used, and not 

 the differences in amount excreted by different 

 species of plants, that determines whether or 

 not a plant will feed strongly on an insoluble 

 material. 



The writer has in preparation a detailed 

 article dealing with the feeding power of 

 plants and the availability of phosphates. 

 E. Truog 



Department op Soils, 

 Wisconsin Experiment Station, 

 Univeksitt of Wisconsin 



THE SOCIETY OF AMERICAN BACTEBIOL- 

 OGISTSi 

 SYSTEMATIC BACTEEIOLOGY 

 Under the supervision of H. A. Harding 

 A Study of B. suhtilis ty Means of the Classifica- 

 tion Card: H. Joel Conn. 



One hundred and thirty cultures of the B. sub- 

 tilis type, isolated from soil, have been studied by 

 means of the classification card adopted by the 

 society. The definition adopted for B. subtilis is: 

 a large, peritrichic, spore-producing rod, faculta- 

 tive anaerobic in the presence of dextrose, liquefy- 

 ing gelatine, and growing vigorously on ordinary 

 media without chromogenesis, producing a mem- 

 braneous more or less wrinkled growth on the 

 surface of agar. Two questions have been con- 

 sidere.d: (1) Do the determinations called for on 

 the card separate these 130 cultures into more than 

 one species? (2) Does the same culture always 

 give identical results upon repetition of the tests'? 

 In answering the first question half of the de- 

 terminations represented by the "Group Num- 

 ber" on the card were excluded because they are 

 implied by the definition of B. subtilis. The de- 

 terminations taken into account were the fermen- 



1 Abstracts of papers presented at the Philadel- 

 phia meeting, December 29, 1914. 



tation of sugars and glycerin, and the reduction 

 of nitrates. The nitrate reduction determination 

 gives quite clear-cut results and may serve to sep- 

 arate an infrequent nitrate-negative species from 

 an abundant nitrate-positive species. The fer- 

 mentation tests do not give such definite results. 

 They suggest that the 130 strains do not differ 

 from each other in fermentative powers, but give 

 inconstant results with the present technique. 



The second question was answered in the nega- 

 tive as regards the fermentation tests; the nitrate 

 reduction test seemed more constant, but insufS.- 

 eient data is at hand to settle the matter. 



These tests indicate that with our present tech- 

 nique different "group numbers" do not always 

 indicate different species. One of the first steps 

 needed in revising the card is to establish the best 

 methods for making the various determinations. 

 Some Induced Changes in Streptococci: Jean 



Broadhurst. 



Various relatively simple physical and chemical 

 factors (such as changes in temperature and dif- 

 ferences in artificial media) differ greatly from 

 such agents as saliva, intestinal extracts, and 

 pure cultures of other bacteria, in their effects 

 upon the physiological activities of selected 

 strains of streptococci. The physiological effects 

 of the former, especially in the various test media 

 containing the sugars and the related substances 

 suggested by Gordon, are mainly of a negative or 

 inhibiting tjrpe, and apparently temporary only. 



The changes induced by the latter factors (sa- 

 liva, intestinal extracts, etc.) are, however, 

 markedly different. They are changes in kind 

 not in amount of reaction; they are active and 

 usually include new powers, not merely the in- 

 hibition or occasional stimulation of earlier pow- 

 ers or capabilities, and often indicate a complete 

 rearrangement of the fermentative complex. 

 These induced changes have, so far, been practi- 

 cally permanent. 

 A Study of the Correlation of the Agglutination 



and the Fermentation Reactions among the 



Streptococci: I. J. Kligler. 



Bacteria have evolved so little along gross 

 structural lines that it is impossible to differentiate 

 members of the same genus on a merely physical 

 basis. We therefore resort to the more delicate 

 criteria of protoplasmic constitution and physio- 

 logical activity, in which direction remarkable 

 differentiation exists. Tests for the finer struc- 

 tural differences of these organisms are found in 

 their behavior to differential stains, such as the 

 Gram stain, and to the immune substances in- 



