29 



The beneficial results from spraying have, in many cases, becD so great 

 -that, for a time, pathologists were inclined to think it a cure for all kinds 

 of diseases. It is now clearly realized that, notwithstanding its great use- 

 fulness, it has its limitations, that there are many diseases it cannot reach 

 and many others where it should not be relied on alone, but should be 

 used in connection with other remedial measures. 



Soil treatment can be employed in comparatively few cases. Injections 

 of carbon disulphide are sometimes used for certain animal root parasites. 

 Spraying the ground along the row is recommended for the salerotiuia 

 wilt, a disease attacking garden vegetables in the Southern States. Sterili- 

 zing the soil in green-houses, by heating it with live steana from perfor- 

 ated pipes, is now practiced with great success in preventing injury from 

 nematodes and from various soil-inhabitinor fuas:i. 



The great importance of heredity as a factor in controlling plant diseases 

 is only now beginning to be fully recognised. Individual plants, like in- 

 dividual men, vary in their ability to resist disease. Even in plants of the 

 same cultural variety, this difference in resisting power is often qaiie 

 marked. It has long been observed that some varieties are more resistant 

 than others. It is uow found that, like other qualities, this power of re- 

 sistance is inheritable, and that by carefully breeding from the most re- 

 sistant individuals, it is often possible to establish resistant strains or va- 

 rieties. This point was clearly brought out at the i-ecent Plant Breeders 

 Oonfereace ia this city. The case of resistant strains of cotton, described 

 by Mr, Orton, of the Department of Agriculture, was particularly interest- 

 ing. In a very few years he has been able to select strains of cotton, 

 practically immune to the wilt, a disease that has devastated large areas 

 in the Southern States. Spraying to prevent disease is at best an expen- 

 sive and exacting operation, aud cultivators will welcome the day, if it 

 shall ever come, when the breeding and selection of resistant varieties 

 .shall make it no longer necessary. 



REPORT ON A TRIP TO JAMAICA.* 



BY 



Pkof. F. S. Earle. 



Dr. N. L. Britton, Dii-ector-in-Chief, New Fork Botanical Garden : 



Sir, 



In accordance with your directions I sailed for Jamaica on October I6th 

 reaching there on October 20th, and remaining until November 2Gth, 

 The trip was uudertaken on the invitation of the Hon. Wm. Fawcett, 

 Director of the Jamaica Public Gardens, for the purpose of investigating 

 certain diseases of logwood, cocoanuts and other economic plants. My 

 instructions were also to secure living specimens of tree ferns for the Con- 

 servatories, and to collect fungi and other cryptogams for the herbarium. 

 Thanks to the hearty co-operation of the Jamaica Government and of the 

 United Fruit Co , and to the invaluable aid given by Mr, Fawcett and his 

 associates, Mr. Wm. Harris and Mr, Wm, Cradwick the objects of the ex- 

 pedition were succpssfully accomplished. Forty-live specimens of tree 

 ferns representing fourteen or fifteen species were secured and forwarded 



* By permission from the " Journal of the New York Botanical Garden," 

 Jan. 1903. 



