RESEARCH IN PHYTOPATHOLOGY 199 



provide in the epithem tissue all the elements in solution 

 necessary for the growth of bacteria. This ready entrance 

 through the water-pores has also been confirmed by H. L. 

 Russell. As shown by Gardiner the water-glands are con- 

 tinuous with the termination of a fibro-vascular bundle, which 

 thus furnishes a readily accessible channel for the progress 

 of the attack. Kramer found that B. solaniperda works its way 

 into the tuber through the lenticels. Stomatal infection has 

 also been observed by Smith in a disease of Japanese plums, 

 caused by Pseudomoiias priiiii. Waite proved by his experi- 

 ments on Pear Blight that a large proportion of the infections 

 take place naturally by means of the floral nectaries. The 

 stigma is another part of the plant which presents an un- 

 protected mode of access ; and Kissling's work on the biology 

 of Botrytis ciiicrca supplies an instance of very facile infection 

 of the gentian through the anthers and stigmatic surfaces. 



It is necessary to allude to Fischer's theories and mis- 

 statements, as in the English translation of his Lectures, issued 

 by the Clarendon Press in 1900, the same errors are reiterated. 

 This is all the more striking as this translation was published 

 under the author's sanction and enjoyed the advantage of a 

 proof-revision by Marshall Ward. Ward in general held the 

 view that bacteria in association with plant-diseases were 

 but a secondary accompaniment of the malady ; and in his 

 treatise upon Disease in Plants this author makes no allusion 

 to the destruction of cellulose by bacteria, which plays such 

 an important role in the penetration of the cells and the rapid 

 disintegration of living vegetable tissues. 



Some of the earlier observations demonstrating the existence 

 of bacteria which exercise a fermentative action upon the cell- 

 wall have already been mentioned. In 1890 van Senus attri- 

 buted the fermentation of cellulose to a cellulose-dissolving 

 enzyme produced by the symbiotic action of two bacteria, one 

 aerobic and the other anaerobic. Later (1895) Omeliansky 

 isolated, from the mud of the Neva, an anaerobic bacillus which 

 entirely dissolved filter paper with the greatest rapidity. These 

 investigations, however, dealt with organisms acting sapro- 

 phytically. The question of the destruction of the cell-wall of 

 living plants by the action of parasitic bacteria was first 

 definitely established by the researches, published simultaneously, 

 of Laurent and myself (1899). 



