AGRICULTURAL BOTANY, 629 



The author calls attention to llic fact that judfiinjj; by its effect on mitosis, as 

 comparetl \yith the effect of dilute solutions of copper sulphate, distilled water 

 is itself a toxic solution. 



The effects of poisons on the respiration of living and dead plants, as 

 well as on tlie respiratory enzyms, W. Palladin {Jahrb. Wiss. Bot. [Prings- 

 heim], J,l (1901), Xo. J,, iq). J, Sl--'iUl).— The results are given of a series of ex- 

 periments in which the action of certain poisons (quinin, ether, selenate of soda, 

 arbutiu, pyrogallic acid, urethan, and toluol) on etiolated seedlings of Vicia 

 faha, on gladiolus and onion bulbs, and on wheat germs was tested. 



It was found that poisons exert their influence on the protoplasm, and that 

 as a result of this influence numerous reactions may occur in the living plants 

 which may result either in a stimulation or a weakening of resjti ration. The 

 action of poisons on the respiration of growing plants is mainly indirect, but 

 on the resi)iration of dead plants an unmistakably poisonous action is possi- 

 ble. On the respiration of active plants, poisons act not as a stimulant but as a 

 check. The stimulation of respiration by poisons depends on the increased 

 transformation of zymogens to active enzyms. An increased respiration is 

 accompanied by an increased destruction of the enzym, for after the death 

 of the plants the quantities of enzyms in stimulated and controlled portions are 

 equal. 



Investigations on the short roots of Sempervivum and the resulting 

 endotrophic mycorrhiza, F. Zach (Sitsbcr. K. Akad. Wiss. IVienna], Math. 

 Naturw. Kl., 118 {1909), I, No. 3, pp. 185-200, pi. 3, figs. Jr, abs. in Centbl. Bakt. 

 [etc.], 2. Abt., 26 {1910), No. 16-11, p. //90).— It is claimed that in the cells of 

 the so-called short roots of Sempervivum a species of Hyphomycetes is found in 

 evident symbiotic relations with the roots, thus presenting another instance of 

 endotrophic mycorrhiza. 



The constancy of certain physiological characters in the classification of 

 bacteria, H. A. Harding {New York State Sta. Tech. Bid. 13, pp. 3--'il, figs. 

 11). — The author discusses the various efforts made during the last 15 years to 

 find a workable system of classifying bacteria, which finally culminated in the 

 present classification card of the Society of American Bacteriologists, and pre- 

 sents the results of a study of various strains of Pseudomonas campestris in re- 

 gard to the value of the card as a basis for classification of bacteria. 



The group number on this card is a numerical expression of the result of 10 

 physiological reactions, and its value as a basis of classification depends upon 

 the constancy with which the same numerical results are obtained for various 

 strains of a single species. When tested upon 44 strains of P. campestris, the 

 same group number gave constant results and did not break the species into 

 smaller groups, and therefore as far as it applies to this species it is regarded 

 as a satisfactory basis for classification. 



The limitation of the group number system as now constituted lies in the fact 

 that it does not carry the separation to a group synonomous with the ordinary 

 conception of species. It is claimed that further assistance in classification may 

 be expected from pathogenicity toward plants, indol formation, casein digestion, 

 growth in I'schinsky's and Cohn's solutions, and turbidity in broth. 



Studies in pyrophilous fungi, II, F. J. Skavkr and IL 1). Clark {Mycologia, 

 2 {1910), No. 3, pp. 109-12.'f, pis. 3). — In continuation of previous studies (E. 

 S. R., 22, p. 452) the authors give an account of changes brought about by the 

 heating of soils and their relation to the growth of Pyronema and other fungi. 

 Their experiments failed to show the presence of a soluble toxic substance in 

 u.nheated soil which will retard the growth of Pyronema when applied to 

 heated soil. The heating of soils at high teniiH>ratures was found to bring 

 about chemical changes in respect to the extracts obtaine<l from the soil. The 



