232 PHYSIOLOGY [Bot. Absts., Vol. IV, 



1539. Hunter, Albert C, and Charles Thom. An aerobic, spore forming bacillus in 

 canned salmon. Jour. Franklin Inst. 188: 136. 1919. 



1540. MacDougal, D. T., H. M. Richards, and H. A. Spoehr. Basis of succulence in 

 plants. Bot. Gaz. 67: 405-416. 1919.— See Bot. Absts. 4, Entry 244. 



1541. Mondino, Alfonsino. Ricerche anatomiche e morphologiche sulla var. "tuberosa" 

 Asch. dell "Arrhenatherum elatius" M. K. nuovamente trovata in Piemonte. [Anatomical and 

 morphological investigation of var. tuberosa Asch. of Arrhenatherum elatius M. K. recently 

 found in Piedmont.] Atti. R. Accad. Sci. Torino 54: 782-794. 1919.— See Bot. Absts. 4, En- 



1 ry 988. 



1542. Moreau, F. M., and Mme. F. Moreatj. Recheiches sur les lichens de la famille 

 Peltigeracees. [Researches on the lichens of the family Peltigeraceae.] Ann. Sci. Nat. Bot. 

 X. 1: 29-32. 1919.— See Bot, Absts. 4, Entry 1130. 



1543. [Nordstedt, C. F. O.] [Swedish rev. of: Murbeck, Sv. Beitrage zur Bioiogie 

 der Wiistenpflanzen. [Contribution to our knowledge of the biology of desert plants.] Lunds 

 Univ. Arsskr. 14: 36. 1919.] Bot, Notiscr 1919: 166. 1919. 



1544. Petersen, Hexning E. Maglemose i Grib Skov. Undersogelser over Vegetationen 

 paa en nords jaellandsk Mose. [High moors in the woods of Gribs Skov. Investigation of the 

 vegetation of a northern moor.] Bot. Tidsskr. 36: 57-154. PL 1-17, fig. 1-18. 1917. 



1545. Pringsheim, Ernst G. Die Kultur der Desmidiaceen. [The culture of Desmidi- 

 aceae.] Ber. Deutsch. Bot, Ges. 36: 482-485. 1918. — Twelve species of Desmidiaceae and four 

 species of Mesotaeniaceae were obtained in pure culture from fresh material and grown on sil- 

 ica jelly which had been flooded with a nutrient solution of a 0.1 per cent KN0 3 , 0.02 per cent 

 K2HPO4, .02 per cent MgSd. For liquid cultures, soil decoctions were used first and later 

 nutrient media, The purity of the distilled water is a factor of great importance if success- 

 ful results are to be obtained. The reaction of the medium must be neutral or slightly basic; 

 the concentrations of the solution must not be high. KNO3 or Ca(N0 3 )2 in 0.1 per cent solu- 

 tion is the maximum for best growth. Ammonium salts are less suited. Best growth was 

 obtained with calcium nitrate as a source of nitrogen. Leaving calcium out of the nutrient 

 medium had no visible effect because enough of the metal is obtained from the glass contain- 

 ers. Mesotaenium, however, grew very poorly in the absence of calcium. — Ernst Artschwager. 



1546. Rose, D. H. Blister canker of apple trees; a physiological and chemical study. 

 Bot. Gaz. 67: 105-146. 1919. — The author finds that apple bark attacked by Nummularia 

 discreta has about twice the oxidase activity of healthy bark. Measurements were made with 

 the simplified Bunzell asparatus. Oxidation in the apparatus comes to an end only after sev- 

 eral days instead of after a few hours, as stated by Bunzell. This gradual slowing down is 

 shown to be due, in part at least, to increasing hydrogen ion concentration, brought about 

 by the oxidation process itself. The equilibrium reached seems to be a false one, which can 

 be disturbed by the addition of either fresh oxidase reagent or fresh plant material. When 

 tested by the formula for a monomolecular reaction the oxidation figures give fairly constant 

 values for k, thus indicating a linear relation between time and amount of change. Results 

 for catalase determinations are said to show some discrepancies, but justify the general state- 

 ment that the more severely the bark is attacked by the fungus the greater is its catalase 

 activity. Tests with the fungus in pure culture showthat it possesses both oxidase and catalase 

 activity. Macro-chemical tests show that diseased bark has a higher percentage of dry mat- 

 ter, lipoids, alcohol-water-insoluble residue and total nitrogen, but a lower percentage of 

 alcohol-water-soluble material than healthy bark. The percentage of carbohydrates in both 

 tissues seems to be about the same. The tannin content of diseased bark was slightly less 

 than that of healthy bark. The greater oxidase activity of diseased bark is thought by the 

 author to be due to the combined activity of the oxidase of fungus and host to lower acidity 

 ( P H 5.61 for diseased bark, and P H 5.15 for healthy bark) and possibly to a greater degree of 

 dispersion of the oxidizing agent. — D. II . Rose. 



