Vol. 



:YII. No. .■.■ 



TB.E AGRIGCLTrSAL N'EY/CS, 



.71 



For some years the plane has beeu used on the Experi- 

 ment Station, Peradeni^-a, as a green manure for rubber, and 

 has been regularly cut four or live times a year with the 

 object of adding humus to the soil. The average quantity 

 of green material per acre per year, has been found to be: 

 first year after planting, 29,000 1b.; second year, 77,000 ft.; 

 and third year, 91,900 lb. I'nder these conditions it is kept 

 at an average height of 2 feet. In .Java it is likewise used 

 as a green manure plant. It is commonly employed in young 

 coffee and rubber plantations, and lias been e.^perimented 

 with on tea estates. 



It is also used in .Java as a light shade for Kobusta coU'ee, 

 and is being similarly employed at the Peradeniya Kxperi- 

 ment Station, where it seems to be well suited for the pur- 

 pose. As shade trees the plants are allowed to grow to about 

 ' 10 feet in height, and are lopped twice a year, the loppings 

 being use<l as mulch around the coffee trees. 



In Mauritius, where the plant grows wild over extensive 

 areas, it is cut regularly every year or every alternate year 

 for fuel. The individual stems of the plants cut out for 

 this purpose have a diameter of between 2 and 3 inches. 

 ■Under Mauritian conditions, trees left for years uncut rarely 

 attain a height of more than 1.5 to IS feet. In .Java the 

 trees grow to a height of 24 feet. In Mauritius the 

 plant is found mainly in the dry zone, and is encouraged as 

 a light shade in fibre plantations. In the neighbouring 

 island of liodriguez, large tracts of land are covered with 

 Leiicaena i^/aiica. Fuel is cut from these lands for local 

 purposes, the leaves are collected for feeding cattle and 

 goats, and the dry seed for e.xport to Mauritius, where it is 

 «reatiy appreciated as a cattle food. 



Catlle are very fond of the leaves of Lcucaeiia i^lauca, 

 and so are goats, herds of these animals being in some places 

 housed, and fed solely upon leaves of the plant. An analysis 

 of the leaves shows that they are particularly rich in nitrogen 

 and potash salts. 



The .seeds are also a valuable food, rich in nitrogen, and 

 may be fed to cattle, sheep, or goats. Neither the leaves 

 nor the seeds, however, should be fed to horses, as they cause 

 an irritation of the skin, with subsequent lo.ss of hair from 

 the mane and tail. 



On account of the hard seed-coat it is usual in practice, 

 before feeding them to stock, either to boil the .seeds until the 

 seed coats burst, or to crush the seeds dry in an ordinary seed 

 €ru.sher. The latter practice is generally recognized in .Mauri- 

 tius as being the more satisfactory. 



In the Philippine.s, l.titcaena ;^liuii:a is u.sed to provide 

 shelter for seedlings in the forest plantations. The young 

 forest trees are afforded a light shade by the I.ciumwi g/aiica, 

 and when ihey have attained a fair size it is cut out and 

 used as fuel. F.xperimental plots have yielded average 

 returns of 10 cords of fuel per acre per year. The fuel is 

 considered to be a high-class fuel wood, with a straight grain, 

 splitting easily. The leaflet from which the above informa- 

 tion is taken, considers that under average conditions in 

 <>ylon, the first cutting of wood would be possible at the end 

 -of three years after planting. 



J.itioxciia i^laiaa is also reported to be a soil renovator. 

 It is a general experience in the eastern countries where it 

 is being grown that soil, after having been under this 

 plant and subsequently taken into cultivation, is of good fer- 

 tility, and there are instances of poor land having b^en im. 

 proved by being allowed to remain for some years under it. 



The leaflet concludes that the plant is most suited in 

 'Ceylon to semi-tt'ipical conditions, and to rho-*e lo.ja'ities 

 that Jo not have too high a rainfall. 



THE SOURCES AND CHANNELS OF 

 INFECTION IN HOG CHOLERA. 

 In a report issiieQ by the Bareiu 'A Animal Industry, 

 I'nited States Department of Agriculture, in 1 889, on Hog 

 Cholera, the sources and channels of infection were enumer- 

 ated as follows: — 



1) Figs purchased from infected herds, or coming ia 

 contact with those from infected farms, or running ovec 

 grounds which had been occupied by disea.sed swine two or 

 three months previously. 



(2) Infected streams 'nay communicate the disease to 

 herds below the source of infection. 



(3) Infection may be carried in teed, on implements, 

 and on the feet and > lotbing of persons coming from infected 

 herds and premi.^es. 



(4) Winds, insects, birds, and various animals may 

 tran.sport hog cholera virus. 



This statement of the ways in which hog cholera is 

 spread forn>s the basis of the present sanitary regulations 

 with regard to this disease in the United States. In actual 

 practice, however, one or more of these channels of infectioa 

 may be of preponderating importance, and the determinatioa 

 of such relative importance might greatly simplify the diffi- 

 cult problem of sanitary control. Accordingly, Messrs. M!. 

 Dorset, C. N. McBryde, W. B. Niles, and J. H. Rietz, of the 

 Bureau of Animal Industry, United States Department of 

 Agriculture, have recorded in the Jijurnal oj Agricultural 

 A'tjYfl.'r/?, April S, 191.S, a series of experiments conducted 

 by them in investigating this question. 



The authors state that although the data obtained froak 

 these experiments are not sufficient tn warrant sweeping con- 

 clusions, the results are nevertheless quite suggestive, and 

 they serve to bring out some interesting points which may be 

 summarized as follows: — 



(1) The fact that tlie blood, excreta, and eye and nose 

 secretions of hogs sick <jf cholera contain the virus of the 

 disease has long been well established. When injected into 

 healthy hogs, the eye and nose secretions and f;eces were 

 found to be infectious on the third day after infection: the 

 urine was regularly infectious by the fourth or fifth day, and 

 the blood was infectious as early as the first day. It is to 

 be noted that the eye and nose secretions may be infectious 

 before there is any visible discharge from those organs. 



(2) Healthy pigs were associated with cholera-infected 

 pigs for forty-eight hour periods on every second day from 

 the first to the eleventh day after infection. With the exception 

 of tho.se exposed during the Srst forty-eight hour interval, all 

 contracted hog cholera. iDiher pigs exposed to choleia-infected 

 pigs seventeen and twenty-one days after infection also 

 contracted the disease. It is evident, therefore, that cholera- 

 infected pigs may transmit the disease by contact at; 

 practically all stages of the disease, even before the appear- 

 ance of visible symptoms, and before the animal can be 

 recognized as sick. 



(3j Healthy pigs were placed in pens with pigs which 

 had recovered from attacks of hog cholera. Other healthy 

 pigs were inoculated with blood from the recovered pigs. 

 None of the pi^s associated in this way with recoveied pigs 

 developed h'lg cholera. 



(4) Healthy pigs were exposed for long periods of tiiae 

 10 pigeons which passed daily from a heavily infected pen, 

 only 111 feet away, containing sick and dying pigs, to the psa 

 i;ontaining the healthy ones. None -A th^ exposed pigs in 

 this experiment d-iveloped cholera While the asiumption 

 would hardly be w;.rraDted that p.geons ntv^r convey hog 

 ob.;.lfia, it does n;>t seeiu likely th.^t they a.r« often corj -.erLii^ 

 in the spread of this diseaae. 



