243 



'In 1895 these first trees fruited ; the seeds were carefully col- 

 lected and planted in nurseries, and in 1 895-6 about 8,000 plants 

 were put out in places where shade was wanted for the cacao trees. 

 These trees, aged eight to nine years now, are a beautiful sight ; 

 they have attained a height of 36 to 45 feet, and have an average 

 circumference of 33 inches. 



' At about four or five years the Castilloas easily outgrow the 

 cacao trees and commence to give them a little shade. As they 

 plant up Castilloas on the property, they kill out the " Bucares," 

 or other shade trees, ring-barking them with the axe at about a 

 yard above the ground. 



'The yield of Castilloa plantations is no longer to be doubted ; 

 the result obtained at Ocumare is a new proof, but the experiment 

 made by General Fonseca is specially remarkable as it shows 

 that the Castilloa can be grown among cacao trees without in any 

 way harming their production. Indeed, at Ocumare they have 

 noticed no diminution in the number of pods carried by the trees 

 shaded by Castilloa, nor any change in the quality of the bean.' 



In the same number of the Tropical Agriculturist (p. 529) the fol- 

 lowing extract is published from a letter from * a well-known 

 planter at Matale,' Ceylon, in which he sums up his experience in 

 regard to Castilloa and cacao as follows : — 



'I have very large Castilloas growing both along roads and also 

 scattered through cacao, the latter of about fourteen years' growth 

 showing no evidence of prejudicial influence from the Castilloas. 

 My clearing of some 30 acres of Castilloa and cacao planted to- 

 gether six years ago so far supports the contention that these two 

 products may be grown together.' 



RECENT DEVELOPMENTS IN AGRICULTURAL 



SCIENCE 



From a Paper by MR. A. D. HALL, Director of the Rothamsted Ex- 

 perimental Station {Lawes Agricultural Trust Committee). Har- 

 penden, England, read at the Meeting of the British Association at 

 Johannesburg, Aug. 30, 1905- 



NITROGEN FIXING BACTERIA. 

 One of these. Bacterium radicicola, although widely distributed 

 as it is in the soil, yet is not universally present ; heaths and peaty 

 soils, for example, that have never been under cultivation frequently 

 lack it entirely ; consequently, it is impossible to obtain a satis- 

 factory growth of leguminous crops until this class of land has 

 been inoculated with the appropriate organism. Again, although 

 but one species of bacterium seems to exist, yet several investiga- 

 tors have found that by its continued existence in symbiosis with 

 particular host plants it has acquired a certain amount of racial 

 adaptation, so that, for example, clover will flourish best and 

 assimilate the most nitrogen if it be inoculated with the organism 

 from a previous growth of clover, and not from a pea or a bean 



