397 
the Physiology of Parasitism. II. 
Death of the epidermal cells in advance of the penetration of the 
cuticle by the germ tube was never found to occur. Even after penetration 
the walls of the epidermal cells usually swell prior to the disorganization 
of the protoplast. There is thus no microscopic evidence for the secretion 
by B. cinerea of a special toxic substance other than the cell- wall-dissolving 
enzyme. 
The results of a microscopical study of the early stages of infection of 
a leaf by the germ tube of Botrytis cinerea are thus in full agreement with 
the purely physiological observations of Brown (1 and 2). 
Literature cited. 
1 . Brown, W. : Studies in the Physiology of Parasitism. I. Action of Botrytis cinerea. Ann. 
Bot., vol. xxix, 1915, p. 313. 
2 . : Studies in the Physiology of Parasitism. III. On the Relation between the 
‘ Infection Drop’ and the underlying Host Tissue. Ann. Bot., vol. xxx, 1916, p. 399. 
3 . Busgen, M. : Ueber einige Eigenschaften der Keimlinge parasitischer Pilze. Bot. Zeit., 
vol. li, 1893, p. 53. 
4 . Durand, E. J. : The Differential Staining of Intercellular Mycelium. Phytopathology, vol. i, 
1911, p.129. 
5 . Errera, L. : Sur l’emploi de l’encre de Chine en microscopie. Bull, de la Soc. Beige de 
Microscopie, t. x, p. 478. 
6. Miyoshi, M. : Penetration of Membranes by Fungus Hyphae. Jahrb. f. wiss. Bot., vol. xxviii, 
1895, p. 269. 
7 . Nordhausen, M. : Beitrage zur Biologie parasitarer Pilze. Jahrb. f. wiss. Bot., vol. xxxiii, 
1899, p. 1. 
8. Ritter, G. : Traumatotaxis und Chemotaxis des Zellkernes. Zeit. f. Bot., vol. iii, 1911, p. 1. 
9 . Smith, R. E. : The Parasitism of Botrytis cinerea. Bot. Gaz., vol. xxxiii, 1902, p. 421. 
10 . Voges, E. : Die Bekampfung des Fusicladium. Zeit. f. Pflanzenkrank., vol. xx, 1910, p. 385. 
11 . Ward, Marshall : A Lily Disease. Ann. Bot., vol. ii, 1888, p. 319. 
12 . Welsford, E. J. : Conjugate .Nuclei in the Ascomycetes. Ann. Bot., vol. xxx, 1916, p. 415. 
EXPLANATION OF FIGURES IN PLATE X. 
Illustrating Prof. V. H. Blackman and Miss Welsford’s paper on Infection by Botrytis cinerea. 
The host tissue in every case is that of the leaf of Vicia Baba. 
Fig. 1. Germinating spore. x 1,200. (Leitz water-immersion objective.) 
Fig. 2. Germinating spore, x 1,200. (Leitz water-immersion objective.) 
Fig. 3. Germinating spore: older stage showing a slight mucilaginous sheath, x 1,200. 
Leitz water-immersion objective.) 
Fig. 4. Germinating spore : older spore showing thick mucilaginous sheath, x 1,200. (Leitz 
water-immersion objective.) 
