348 SUMMAKY OF CURRENT RESEARCHES RELATING TO 



ortranisms that directly or indirectly take part in the heating process. 

 The three most prominent organisms are a form of BaeUlm coJi, Oidium 

 lactis and Bacillus calfactor, sp. n. He gives accounts of each and of their 

 behaviour in different cultures. Miehe also isolated a number of fungi 

 and bacteria that find their natural habitat in the overheated mass of 

 hay. Actinomyces tliermophihis formed white streaks and spots on heated 

 grass that was still full of sap. Thermomyces lanuginosiis was gathered 

 when the temperature was at the highest point ; Thermoascus aurantiacus, 

 g. et sp. n. occurred in tiny yellow spots. It is one of the lower 

 Ascomycetes near to Gymnoascus. Asperyillus fumigatus was frequently 

 met with ; it is not necessarily a thermophil fungus, but it grows best 

 at blood heat. Mucor piusiUus was very common on the warm hay. 

 The zygospore of this species was found for the first time liy Miehe. 

 Mucor corymhifer was also isolated and cultivated. These fungi are more 

 or less pathogenic, and it is a new discovery that their natural habitat 

 should be heated plant remains. The author thinks that other 

 inimical fungi and bacteria probably owe their propagation to the hot 

 beds of manure, and that the prevalence of the tubercle bacillus may be 

 due to the many natural culture-beds. 



Some of the experiments were directed to gauging the rise and the 

 amount of temperature in a mass of heated hay. On the second day 

 the mass began to sweat ; by the sixth day the highest point, 68 '5° C, 

 was reached in the centre of the rick. It was found that at a certain 

 stage self -sterilisation occurred ; the organisms all died off. The reason 

 for this was, however, not satisfactorily demonstrated. 



Other chapters are devoted to the heating of tobacco leaves, which 

 plays a large part in the ripening process. The questions of heat and 

 respiration are discussed. The author fancies that such self-heating 

 must have occurred in the early days of the earth's history in the 

 gigantic masses of piled-up plant remains, and that this must have been 

 an important factor in the formation of coal. 



J. Adams * draws attention to the same subject, pointing out the high 

 temperatures at which fungi can grow. He tested the heated ricks, and 

 found that the thermometer rose to b~\^ C. (equal to 135|° F.). The 

 hottest parts of the rick were completely infested with a fungus bearing 

 sporangia, a species of Mucor in all stages of development. He noted 

 still another fungus, with brown septate mycelium but without 

 fructification. 



Plant Diseases. — Yon Tubeuf t ^Tites on the very wide dispersion 

 of the fungus Trametes Pini. It occurs over the whole of Germany up 

 to Alpine regions. It attacks not only the native Conifers but also 

 foreign species that have been introduced. Traces of its ravages have 

 been identified in fossil wood. 



P. Magnus % has described a disease of mushrooms due to Mycogone 

 perniciosa. It produces chlamydospores and VerticiUium conidia and 



* Irish Naturalist, xv. (1906) pp. 254. 



+ Nat. Zeitschr. Land. Forst., 1906, heft 2. See also Centralbl. Bakt., xvii. 

 (1907) pp. 812-1.3. 



X Natur. Rundschau, xxi. (1906) 3 pp. See also Bot. Centralbl. civ. (1907) 

 p. 837. 



