740 EXPEEIMENT STATIOIT RECOED. 



Eysenhardtia polystachya, the source of the true lignum nephriticum 

 mexicanum, W. E. Saffoed {Jo%ir. Wash. Acad. ScL, 5 {1915), No. llf, pp. 503- 

 517, flffs. 2). — In this article, which is based on a paper read before the Botanical 

 Society of Washington, the author establishes the identity of lignum nephriti- 

 cum^exicanum, a nephritic wood remarkable for the blue fluorescence of its 

 infusion in spring water, and which was celebrated throughout Europe in the 

 sixteenth century as a diuretic. It proves to be the wood of a leguminous tree 

 (E. polystachya) occupying an extensive range in the interior of Mexico. The 

 species is described in detail. 



-l. 



DISEASES OF PLANTS. 



The investigation of physiological plant diseases, R. E. Smith (Phytopath- 

 ology, 6 (1915), No. 2, pp. 83-93). — According to the author the term "physi- 

 ological " or " nonparasitic " disease has come into use to describe troubles 

 due to an autogenous functional disturbance rather than to the presence of a 

 foreign organism. The information regarding a number of these diseases is 

 reviewed and the author concludes that there is no such thing as an established 

 group of physiological or nonparasitic plant diseases for the kind of troubles 

 which have been described. They are all considered more or less obscure dis- 

 eases of unknown etiology as yet unaccounted for. He claims that the only 

 positively known inciting factors in plant diseases, excluding direct trauma- 

 tisms, are parasites. 



A suggestion of a new phase of the problem of physiological diseases of 

 plants, C. B. Lipman (Phytopathology, 5 (1915), No. 2, pp. 111-116). — Largely 

 upon the basis of the author's Investigations on mottled leaf of citrus trees 

 (E. S. R., 31, p. 4.50), he proposes as a justified theoretical consideration to 

 connect certain functional troubles in plants known as malnutrition or as 

 physiological diseases with a definite lack of the specific plant food element, 

 nitrogen, in available or usable form. 



Bactericidal products in healthy and diseased plants. — I, Healthy plants, 

 R. J. Wagner (Centbl. Bait, [etc.], 2. Abt., 42 (1914), No. 21-22, pp. 613-624, 

 figs. 5). — This first report deals with the natural immunity of plants, detailing 

 studies made with three different bacteria named. 



It is stated that in healthy plants three classes of antibacterial products may 

 be found, namely, agglutinin, tending to limit bacterial movement, lysin, tending 

 to dissolve bacterial membranes, and substances limiting multiplication of 

 spores and of bacteria possessed of resistant membranes. To these may be 

 added as a possible factor a heightened acidity of the cell sap. 



[Adaptive specialization of vegetable parasites], F. Heske (Centbl. 

 Gesam. Forstiv., 40 (1914), Nos. 7-8, pp. 272-278; 9-10, pp. 369-375).— The 

 author reviews recent developments regarding biochemical phenomena noted 

 in plants, and discusses, in connection with the probable activities of ferments 

 as related to the specialization of certain parasitic organisms, the apparent 

 j)ossibilities as regards the gradual production of ferments adapted to this work. 



Disease resistance in plants, O. Appel (Science, n. ser., 41 (1915), No. 1065, 

 pp. 773-782). — In this paper, which was presented as a lecture before a number 

 of agricultural colleges in this country, the author points out various problems 

 in connection with resistance to plant diseases, and states that while the present 

 ^ methods of combating diseases should not be abandoned, efforts should be 

 made to, find the causes of immunity, and after solving this question to deter- 

 mine without infection the disease resistant qualities in different varieties and 

 individuals in order to establish the desired resistance and at the same time 

 eliminate undesirable qualities. 



