Fungi, Bacteria und Pathologie. 335 



the seed ior some time before treatment. A 3 hours soaking in cold 

 water and a 15 minutes treatment with 187« formalin Solution does not 

 materially injure the vitality of the wheat, while the smut spores were 

 killed by such treatment. However, in actual practice this treatment does 

 not always kill the smut. Seeds soaked 4 hours in cold water and 

 treated with hot water for ten minutes at 120 degrees F. gave slightly 

 better germination of the wheat than did untreated seeds. With the smut 

 the lower limit of effective treatment was 110 degrees F. for 5 minutes 

 and 105 degrees for 10 minutes. P. Spaulding. 



Ward, H. Marshall, Experiments on the Effect of 

 MineralStarvationontheParasitismoftheUredine 

 Funsus Piiccirüa dispersa on Species of Bromus. 

 (Proceedings of the Royal Society. LXXI. Dec. 1902. 

 No. 469. p. 138—151. 4. Tables. 4 fig.) 



In previous work (Centralblatt XC. p. 626) the author has 

 shown, that the anatomical differences on the part of the host- 

 plant, such as the size and number of stomata, hairs, etc., do 

 not suffice to explain the remarkable phenomenon of predis- 

 position to, or immunity from, infection of the host by this 

 parasite. He now, by means of a large number of experiments 

 carried out mainly with Bromus secalinus, describes the effect 

 of starving the host plant of one or other of its necessary food 

 materials. 



The Bromes were cultivated in beakers filled with and 

 supplied with various Solutions of nutrient salts; precise details 

 of the experiments are given, and the results set forth in ela- 

 borate tables, from which the following conclusions are drawn: 

 1. Lack of minerals in no way secured immunity from infection, 

 though seedlings deficient in phosphorus or in nitrogen tended 

 to show retardation of infection. 2. Mineral starvation makes 

 itself feit quantitatively in the number of uredo- 

 spores which can be produced by the fungus in the tissues of 

 the starved leaves. 3. The spores reared on starved seedlings 

 are capable of normal germination and infection, and that in 

 proportions which showed no relation to the degree or kind of 

 starvation of the seedling which bore them. 



If the host plant is highly fed, its tissues yeild more food 

 materials for the fungus ; the latter can develop a larger myce- 

 lium and produce a larger crop of spores. But so long as the 

 host plant is capable of living at all, it is a perfectly satis- 

 factory prey for the fungus in its tissues, so far as quality of 

 fungus food is concerned. 



In the words of the author, we must conclude for the 

 present, that" (1) the starvation of mineral food-substances, 

 although it reduces the size of the host plant, and seriously 

 diminishes the quantity of spores which the mycelium can 

 give rise to on its leaves, does not affect either the viru- 

 lence of such spores, or the p re d isp osi tion to infection 

 of the leaves of the Brome concerned. 



Moreover (2), in view of the results with the highly- 

 manured seedlings to which horse-dung decoction or normal 



