686 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Diseases of Plants.* — An account is given of Plasmodiophora 

 Brassicse, the way in which it is propagated, and the best means of 

 preventing or curing the disease. 



A paper f on Larch and Spruce Fir canker, by G. Massee, gives 

 the results of the observations and experiments of many years. He 

 discusses the various stages of the diseases and the probable manner 

 of infection. He considers them to be entirely wound parasites, all 

 infection experiments having failed on uninjured bark. The Larch 

 canker is caused by Dasyscypha calycina ; the fungus causing the spruce 

 disease is D. resinaria. The latter is frequently enabled to enter the 

 tissue of the host through wounds made by a small parasitic fungus 

 Exosporium sp. Methods of prevention and cure are suggested. The 

 paper is well illustrated. 



Another paper $ deals with Cucumber and Melon-leaf blotch, due 

 to a parasitic fungus Cercospora Melonis. It occurs only in green- 

 houses where the air is hot and moist. Preventive measures are recom- 

 mended. 



Canker in Apple-Trees.§ — Hasselbring has discussed the various 

 diseases affecting the bark of apple-trees popularly described as canker. 

 The most common instance ot the disease in Illinois, U.S., is due to 

 a fungous parasite, Nummularia discreta. It is a wound parasite and 

 gains entrance to the tree through openings in the bark caused by 

 pruning or by accidental injuries. It produces extended blackened 

 areas, and the bark cracks and finally crumbles away. The affected 

 branch is always killed by the fungus. Badly diseased limbs should 

 be cut and burned, and wounds in the tree should be painted with some 

 antiseptic solution. 



Economic Fungi. || — There is a considerable number of the smaller 

 fungi that are used in the manufacture of various articles of commerce, 

 and Prof. Wehner has given an account of some of the most important. 

 He cites some of the forms of yeast used in brewing, in the East, as 

 well as Aspergillus Oryzse, which is employed in Japan in the making 

 of Soja sauce. Aspergillus niger is used for the production of oxalic 

 acid ; Citromycet Pfefferianus is employed in the manufacture of citric 

 acid. He takes note also of Penicillium glaucum which is mixed with 

 the cheese curds to form the green veins of Roquefort and Gorgonzola. 

 The Chinese make a red colouring matter from Monascus pjurpmreus, but 

 the method employed remains a secret. The author also mentions some 

 other fungi which are used as colouring agents. 



Pathogenic Fungi. IT — L- Gedoelst calls this book a technical guide 

 to vegetable parasitology. His aim has been to provide a manual that 

 can be consulted alike by the physician and the botanist. He gives 

 descriptions of the various fungi that have been found to cause diseases 

 of the animal body and gives the best methods of isolating and culti- 



* Journ. Board of Agric, ix. (1902) pp. 145-9 (1 fig.). 

 t Tom. cit., pp. 176-88 (3 pis.). 

 J Tom. cit.. pp. 196-8 (1 pi.). 



§ Bull. No. 7u Univ. of. 111. Agr. Station. See also Gard. Chron., xxxii. (1902) p. 60. 

 "|| Zeitschr. angew. Mikr., viii. (1902) pp. 89-90. 



f ' Les Champignons Parasites de l'Homme et des Animaux Domestiques,' par 

 L. Gedoelst (Brussels, 1902) pp. vi. and 199 and 124 figs. 



