259 



plant there is la certain acidity which is most favorable for the life 

 processes of that species. Unquestionably in many cases soil acid- 

 ity, by limitiiii,^ the supply of lime available for plants, affects the 

 acidity of the juice or protoplasm of these plants. The importance 

 of a -jH'oper regulation of plant acidity in relation to vital plant 

 processes should be noted. 



" In the life processes of i)lants, acids are formed, some of 

 which are probably simple by-products. Lime and other bases are 

 needed to neutralise these acids. Plants high in protein are usual- 

 ly high in lime and other bases indicating' the formation of acids 

 in protein synthesis. If the supply of lime and other bases is in- 

 adequate, the acidity of the plant Juice rises to a certain extent 

 which is limited because the accumulation of acids probably de- 

 creases tlie rate of the processes which produce acids. A condition 

 of self regulation thus probably exists and death due to over-acidity 

 is prevented. Slow growth and a weakened condition however, 

 result as is the ease with plants of high lime requirement growing 

 on acid soils. 



" In plants there are many " buffer " substances which to a 

 certain extent help to maintain a more uniform acidity and prevent 

 rapid and excessive alterations, as would result especially from* 

 diurnal changes in plant processes. Bases are however usually 

 needed in the formation of these "buffer" substances." 



T. F. C 



Red Ring Disease of Coconuts. 



The following extracts are taken from a report read by Mr. 

 W. Nowell, I). I. C, Mycologist, Imperial Department of Agri- 

 culture, Trinidad on Oct. 16, 1919, and published in the "Agri- 

 cultural Xews " A^ol. XYIII, Xo. 460. It i? considered it may 

 be of interest to 'local growers of coconuts. 



"■ It may be remembered tliat during my last visit I had in- 

 cidental opportunities of making observations on the so-called root 

 disease of coconuts, and announced the invariable association of 

 the disease in all cases examined, with a minute thread worm or 

 nematode. The matter was not then sufticientlv advanced for the 

 issue of a Tejiort. and the investigation is still "far from complete. 



In the first place it must lie stated that the connexion of the 

 disease with the nematode worm has been abundantly confirmed. 

 Xot only is the worm present in close association Avith the first 

 appearance of the disease in anv organ of the plant, but infection 

 experiments, with material to all appearances pure have resulted 

 in complete and typical infestation of the inoculated trees with the 

 reproduction of all the symptoms of the disease, the parallel con- 

 trols remaining healthy. The proof cannot be considered absolute, 

 but it comes nearer to certaintv than is the case with very many 

 plant diseases in which (causation is regarded as established. 



'• The worm has been descrii)ed as a new species Aphelenchus 

 cocophila, by Dr. X. A. Cobb, of the United ^States Department 

 of Agriculture, who lias prepared a paper on its characteristics for 

 the forthcoming number of the West Indian Bulletin. 



