20 



STUDIES IN BACTERIOSIS. V 



FURTHER INVESTIGATION OF A SUGGESTED BAC- 

 TERIOLYTIC ACTION IN P ROTE A CYNABOWES 

 AFFECTED WITH THE LEAF-SPOT DISEASE 



By SYDNEY G. PAINE and EMILY M. BERRIDGE. 



{From the Department of Plant Physiology and Pathology, Imjierial 

 College of Science and Technology, London.) 



(With 1 Text-figure.) 



In a previous paper^ attention was drawn to the possible occurrence of 

 a bacteriolytic process analogous to that found in animals. The existence 

 of some such phenomenon was indicated by the marked localisation of 

 the disease, by the difficulty experienced in the isolation of the parasite 

 from the diseased areas, and by the appearance of the diseased tissue, 

 the cells of which showed no well-defined micro-organisms. The presence 

 of bacteria was suggested by the granular appearance of the contents of 

 many of the cells, giving the impression of a bacterial zoogloea embedded 

 in resinous material. The degree of granulation of this substance varied 

 in different cells, and its affinity for bacterial stains varied in proportion 

 to the degree of granulation. These observations seemed to suggest a 

 process of dissolution of the bacterial zoogloea. 



The present work was undertaken to elucidate this phenomenon and 

 to determine the fate of the bacteria after they had invaded the leaf 

 tissue and produced the leaf -spot. 



Fresh isolations of the parasite, Pseudo?nonas Proteamaculans P. and 

 S., were made and again the old difficulty was experienced; of twenty- 

 two attempts, only five yielded cultures of the causal organism. It does 

 not appear that any seasonal fluctuation could account for the numerous 

 failures^ since of the five successful attempts one was made in November, 

 two in March, and two in July. 



The method employed was as follows: The surface of the leaf was 



1 Paine, S. G. and Stansfield (1919). A7m. A])}). Biol, vi, p. 27. 



