172 PATHOLOGY [BoT. Absts., Vol. VII, 



dispersa, P. malvacearum, Phytophthora infestans, Plasmopara viticola, Fusicladium den- 

 dritium, Sphaerotheca mors-uvae. Hemileia vastatrix, Chrysophlyctis endobiatica, Fusarium 

 vasinfectum, F. tracheiphilum, F. niveum, and Heterodera radicicola. — Charles Chupp. 



1155. Ehbenberg, p. Der Einflusz des Bodens und der Diingung auf Pflanzenkrank- 

 heiten. [The effect of soil and manuring upon plant diseases.] Fuhlings Landw. Zeitung 68: 

 402-412. 1919. — A popular discussion touching on various soil conditions and various manurial 

 additions to the soil that may directly or indirectly cause plant diseases. — A. T. Wiancko. 



1156. Fofix, Et. La necrose du liber de la tige der pomme de terre atteinte de la maladie 

 dite "de I'enroulement." [The necrosis of the wood of the stem of potato occurring in the 

 disease called "leaf roll."] Compt. Rend. Acad. Sci. Paris 170: 133(>-1339. 1920.— At the 

 beginning of the necrosis there is first a pectic reaction with ruthenium red safranin, or 

 carmin alum. Later there appears lignin and either cutin or suberin. It therefore appears 

 that the disease is in the nature of a pectic degeneration. — C. H. Farr. 



1157. Heinricher, E. Zur Kenntnis der Verhaltnisse zwischen Mistel und Birnbaumen. 

 [Relation between mistletoe and pear.] Zeitschr. Pflanzenkrankh. 30:41-51. 1 fig. 1920. — 

 In certain localities mistletoe occurs on pear trees very abundantly; in others it is exceed- 

 ingly rare. An attempt is made to explain this contrast and especially the local frequency 

 of the "pear mistletoe." It is emphasized that abundant development of the mistletoe on 

 the main trunk of pear trees, particularly of younger trees, is most injurious. Several cases 

 are referred to in which young bearing trees were killed through attacks by the mistletoe. 

 In nature, however, attacks occur less frequently on young trees than on older ones. An 

 infection of the main axis of young trees is not frequent. Mistletoe prefers tree tops. One 

 case is related wherein a pear tree reacted most rapidly against a first infection with mistle- 

 toe. A second infection also failed at first, but developed later with considerable vigor. 

 This case, the author states, is of interest, since it does not seem to permit of any other expla- 

 nation, but that the reactions against seed and viscin of mistletoe are due to antagonistic 

 action of the pear tree. The author suggests the possibility of the development of an "anti- 

 toxin" in the pear tree through the toxin of the mistletoe. — H. T. Giissow. 



1158. JoDiDi, S. L., S. C. MouLTON, AND K. S. Markley. The mosaic disease of spinach 

 as characterized by its nitrogen constituents. Jour. Amer. Chem. Soc. 42 : 1061-1070. 1920. — 

 See Bot. Absts. 7, Entry 442. 



1159. JoDiDi, S. L. A mosaic disease of cabbage as revealed by its nitrogen constituents. 

 Jour. Amer. Chem. Soc. 42: 1883-1893. 1920.— See Bot. Absts. 7, Entry 441. 



1160. Levine, Michael. The behavior of crown gall on the rubber tree (Ficus elastica). 

 Proc. Soc. for Experimental Biology and Medicine 7: 157-158. 1920.— After summarizing 

 briefly the present status of studies upholding the crown gall in its analogy to animal cancer, 

 the author reports that "It was found that Bacterium tumefaciens inoculated into the apical 

 internode of the branches, into the leaves or main stem of the rubber tree, Ficus elastica, 

 stimulates the development of a neoplasm in the region of inoculation of a benign or malig- 

 nant nature. The crown galls so formed, in this plant, are of two kinds, one in which growth 

 is uniform and appears to be a swelling, the other is the characteristic convoluted type indi- 

 cating a peripheral growth of isolated nodules. The crown gall in Ficus elastica after a 

 number of months of active growth becomes hard and finally dies. This is associated with the 

 differentiation of the tissue which converts the gall into a mass of parenchymatous cells and 

 nodules of woody fibers. The central portion of the crown gall which generally lies near 

 the wood cylinder disintegrates. — The invasion of the stem by the new growth does not 

 destroy the entire conducting system of the stem, yet that portion of the stem above the gall 

 dies as well as considerable portion of the stem below. Cultures made from pieces of the 

 crown gall and stem above and below the gall yield only a schizomycete which in appearance 

 is not unlike Bacterium tumefaciens and which when inoculated into the stems of young 



