41 



Bibliography. 



In Ceylon the canker became wide-spread in 1896, but 

 had been occurring there for some years before. Not luitil 

 1898 was it more carefully studied by Carru thers, who 

 in some reports ') recorded the results of his investigations ; 

 thèse were written during his investigations and so bear 

 a preliminary character; a more detailed aceount has 

 however never appeared, so that several points, especially 

 in respect to the cause of the disease, hâve not been 

 fully elucidated. I shall revert to this after the discussion 

 of my own investigations. 



According to Carru thers it is not only the stem and 

 branches of the cacaotrees which are attacked but the 

 fruits as well. In the diseased tissues he found the mycé- 

 lium of a fungus and on the bark the perithecia of a 

 Nectria, which he regarded as the cause of the disease. 



He does not believe that some trees more than others 

 are specially predisposed to the attacks of the canker; 

 an immune variety has not yet been found; vigorous 

 trees as well as unhealthy ones are attacked, when the 

 conditions, necessary for the infection, are présent. In the 

 dampness of the air he sees the principal factor for spread 

 of the disease as it facilitâtes the germlnating of the 

 fungus spores. A considérable part of Carru thers' work 

 has been devoted to the combating of the canker. The 

 remédiai and préventive measures practised by hlm will 



1) .1. B. Carru thers. The Tropical Agriculturist. Vol. XVII, 

 1898, p. 851, Vol. XVIII, 1899, p. 359 and p. 505. 



J. B. Carru thers. Proceedings of the Linnean Society. Oct 

 1900, p. 7. 



J. B. Carru thers. The Tropical Agriculturist. Vol. XXI 1902, 

 p. 441 and 517. 



