268 



The amount of this alkaloid given out by the roots is not incon- 

 siderable. Sesamum in its early stages of growth appears to excrete a 

 greater amount of material than it builds upon its own substance." 



The bearing of these observations on the question of rotation of 

 crops is obvious. 



" The question may, however, be put why cotton, for instance, 

 which grows so feebly near sorghum grows at least as well if not 

 better, after sorghum than after cotton. From experiments now in 

 progress it appears that this is explicable as follows:— 



When cotton is growing near sorghum the roots of the latter exude 

 the toxic substance into the soil in large quantities. This spreads 

 rapidly through the soil into the subsoil especially during the rainy 

 season, and neighbouring cotton plants are not protected by the fact 

 that their tap roots go down far below the zone in which the sorghum 

 roots are situated. When cotton follows sorghum, however, the 

 condition of affairs is different; the toxic substance remaining, at the 

 time of harvesting, in the roots of the previous sorghum crop is now 

 being given out slowly in the course of the decay of these roots, " and 

 is held entangled in the organic matter of the roots, largely in the zone 

 of soil in which the roots of sorghum spread. Each crop thus fouls 

 the soil for a crop of the same variety, whose roots will take the same 

 course as a previous crop, more than for a crop whose roots spread in 

 another layer of the soil. 



The precipitation of the toxic substance by most of the mineral 

 manuresiin common use indicates the manner in which many manures 

 act in increasing crop yields." 



ACALYPHA FRUTICOSA FORSK. 



This plant is a low shrub, bushy in shape with wiry bran- 

 ches, the leaves alternate coriaceous ovate obovate or lanceolate 

 narrowed at the base to a short petiole, crenate, blunt, strongly nerved 

 quite glabrous | to 2 inches long and from i to 1 inch wide. Very 

 variable in size and shape They are glandular at the back and aromat- 

 ic when rubbed. The flower spikes are slender yellow and pubes- 

 cent, one or two inches long covered with very small male flowers with 

 one, two or three female flowers at the base. The female flowers are 

 enclosed in several three toothed bracts, and are about i inch across. 

 Sepals 3 ovate ciliate. Styles strongly fringed and ovary covered with 

 long hairs. It only seems to occur on the east coast of the peninsula 

 where I found it at Pekan in open sandy spots. Mr. Eostado got it at 

 Bundi in Tringanu and Capt. Macgill sends it from Bagan, Kelantan. 

 Rostado gives the name as "Te hutan" Capt. Macgill as "Te'Kampong" 

 as opposed to Te Kadai ; and the latter says that the Malays dry the 

 leaves and drink the hot infusion like tea as a beverage and also for 

 heated body and bowel complaints, and kidney trouble, known as 

 Badang panas, "Sakit P'rut" and "Ayer Kinching Kuning." 



*"That the roots of sorghum and other crops exert an extraordinary 

 toxic ellect when mixed with soil in which plants are then grown has been 

 proved by the writer in a set of pot experiments," 



