ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 617 



Fungal Parasites of Men and Animals.* — Henri Coupin has pub- 

 lished an atlas reproducing the figures of all the microscopic fungi that 

 have been known to cause disease or to infect living beings. It is 

 intended as a useful book of reference for doctors and veterinary 

 surgeons, and will also be helpful to botanists. The text is confined to 

 descriptions of the plates, with a note as to the habitat of the fungus 

 figured. Coupin has added drawings of the higher fungi that are 

 poisonous or suspect as articles of food. A good index completes the 

 volume. 



Value of Chemotropism in the Parasitism of Fungi. + — L. Petri 

 made a series of experiments with Sclerotinia Libertiana, to deter- 

 mine the true nature of resistance to the parasite in the higher plants. 

 He carried out these experiments on various grasses, and describes his 

 methods and the tissues after the various attacks induced by infection. 

 He found that some grasses present a natural immunity against 

 S. Libertiana, though that does not imply an immunity against the cytases 

 elaborated by the fungus. Such immunity is based on certain contents 

 of the cell, which exercise a stimulus of chemotropism against the parasite ; 

 the fungus provokes in it a formation of cytase and of potassium oxalate, 

 and that in turn reacts on and conquers the resistance of the host-cell. 



Gall-fungi4 — L. Petri has made a series of observations on the 

 galls formed by Phylloxera. He finds in the gall several species of 

 fungi growing on the gall tissue, and probably of service as food for 

 the larvae, but he also finds certain fungi parasitic on and killing the 

 Phylloxera ; eggs and larvas, as well as the perfect insect, are attacked. 

 The harmless gall fungi are forms of Ramularia, Torula, Hormodendron, 

 Fusarium, and Dematium pullulans. Those living on eggs and lame 

 belong to other genera. Among them he has isolated species of 

 Acremonium, Cladosporiiim, Hormodendron, Oospora, Alternaria, Macro- 

 sporium, and Nectria. Petri describes these fungi : many of them he 

 considers live only on the dead eggs or larvae, and have not attacked 

 the living organisms. The author discusses the action of the Phylloxera 

 and of the fungi on the leaf. 



Freezing Tests with Aspergillus niger.§ — It has been stated 

 that a close connection exists between high osmotic pressure in plant 

 cells and death by freezing. N. Maxirnow experimented on Aspergillus 

 niger to test this statement. He grew two plants, one with a high 

 percentage of glycerin, or sugar, solution in the culture ; the other was 

 grown as a control culture. After growth was well developed they were 

 reduced to a low temperature, and the carbonic acid given off was 

 carefully observed. Freezing took place at a higher temperature than 

 ice formation. Other results were noted, but chiefly that the osmotic 

 condition of the cells has no connection with the fatality due to 

 freezing. 



* Atlas des Champignons parasites et pathogenes de l'Homme et des Animaux 

 Paris : Octave Doin et Fils (1909) 137 pp. (58 pis.). 



t Atti Reale Accad. Lincei, cccvi. (1909) pp. 545-53. 



J Ann. Mycol., vii. (1909) pp. 254-73 (9 figs.). 



§ Journ. Bot. ed. Sect. Bot. Soc. Imp. Nat. St. Petersbourg, 1908, pp 32-46 

 See also Bot. Centralbl., ex. (1909) pp. 597-8. 



