Mav I, 1 886.] 



THE TROPICAL AGRICULTURIST. 



757 



Diseases of Pt.ants Caused by Thbead 'Wootis.— 

 M. PrilJieux has receutly published a paper ou this 

 subject refcrriug to the nematoij worms whieli (1) 

 psnetrate the interior of leaves aud cause their de- 

 composition ; (3) which produce galls on the flowers 

 of grasses; (3) which produce galls on roots; and 

 (4) those which attack Beetroots. The two lirst worms 

 belong to the genus Tjlcnchus ; the two last are 

 species o£ Heterodera— Gui't/c/itrs' Chnmiile. 



The Giant Caterpillar.— It may mterest some 

 of your readers to hear that the caterpillar figured 

 in your issue of the 20th is very commonly met with 

 iu the hill country of Ceylon. Owing to its ressmbl- 

 ing in colour so closely the bark of the trees ou 

 the leaves of whioh it feeds, it is not readily notice- 

 able, and I usually discovered its whereabouts from 

 the ground beneath the tree being strewn wth drop- 

 pings. It is necessary to handle it with great caution, 

 as the sharp bristles on its back become at once 

 detached on coming in contact with the naked hand, 

 causing intense irritation. When about to turn into 

 the chrysalis state, the larva spins itself a cocoon— 

 or, rather, half a cocoon— firmly attached to the 

 stem, or one of the branches, of the tree on which 

 it has been feeding. From the chrysalis, iu cour.se 

 of time, emerges a large dark-coloured moth, tho 

 sole mission of which appears to be to lay eggs, since 

 whereas it is enilowed with an enormous body, its 

 wings are quite out of proportion, being ridiculously, 

 small and quite unequal to the task of raising it 

 from the ground ; indeed, it was commonly known to 

 us a,s the " wingless moth." The male muth is totally 

 differcut, being less than half the size of the female, 

 with fully developed wings, shaped hke those of tba 

 privet hawk moth, aud a tapering body. I think 

 the larva of the male must also differ from that of 

 the female, since of several specimens which I kept 

 in captivity from the caterpillar to the moth stage, 

 all proved to be females.— ■\\'. F. Laurie, Charlton, 

 Staines. Feb. -Ih.— Field. 



Dr. Buchnkr on the Cameroons.— Dr. Max Buchner 

 gave a lecture on AWduesday in the Architektenhaus, 

 Berlin, in connection with the German Colonial As- 

 sociation, on the value and the future of the Came- 

 roons. Dr. Buchner said that the value of this 

 possession was at present small, but the elements of 

 great prosperity were unmistakable. The present ex- 

 ports came from a zone of proilucfion of not over 

 100 kilometres reckoned from the coast inland. What 

 lay beyond was as yet completely unknown. The 

 Cameroons possessed a rich volcanic soil, which ex- 

 tended from Fernando Po in a north-easterly direc- 

 tion, aud tlie country had .also an abundance of rain, 

 which was a point of great importance. It coudi not 

 be said that there was any great mineral wealth ; at 

 least, no signs of it had thus far been detected. As 

 a plantation and trading colony the Oameroons were 

 of undoubted value, but to encourage emigration thi- 

 ther on any great scale would be criminal. The pro- 

 ducts of the laud included the oil palm, the cocoa 

 palm, cofltee and cocoa, quinine, indigo, caoutchouk, 

 rice, and sugar. The oil palm only grew wild at 

 present, but it could be cultivated. The cultivatiou 

 of the cocoa-nut palm had also been neglected. 

 As to coffee the question of sale had to be considered, 

 and the market was now overrun. Cocoa would pay 

 better, and this could be easily cultivated. The Came- 

 rjon mountains olfereil an excellent ground for cultiv- 

 ating quinine, while rich and sugar were to be grown 

 in the lowlamls. Dr. Buchuer spoke of the necessity 

 of opening up the inland region, and hinted at the 

 po.-isibihty of a railway proving in time remunerative. 

 Meanwhile beasts of burden would have to be used— 

 especially oxen, as they throve better and were cap- 

 able of more work than horses or asses. As elephants 

 were very abundant there— more so than in any other 

 part of Africa— an attempt should be made to tame 

 thim. The ultimate opinion expressed by Dr. Buchner 

 was that the Cameroons wcmld pay the costs of keep- 

 ing and administering it. Africa as a whole was re- 

 garded as a poor country, but the Cameroons belonged 

 to the richest parts.— AifAZytuV German Trade Review. 



The Madras Tea Industkv.— The Madras tea in- 

 dustry IS doms: well. There are 84 plantations, all 

 111 the A izagapatam, Madura, Nilgiris, an.l Malabar 

 districts. The,=e have a total area of 7,.5,';;i acres of 

 which little more than half is .actually under cultiv- 

 ation. Last year the outturn reached 398,04.5 lb. In 

 Travancore there are 27 plantations, occupying a 

 ^nl'l'^.A^'^n '"■'■■•1 °f !'-'87 acres. The total outturn was 

 iU.'i.iJO lbs, of which the whole was black tea.— 

 Jinliim Tta (Jazette. 



The PKii.osonivor Tea Drying. —Mr, Gibbs ((Jibbs 

 aud Barry I writing to a contemporary, remarks as 

 follows :— '• 'J'he whole philosophy of rapid economical 

 and thorough drying may, I think, be summed up in 

 these three points:— 1. That the tea should be kept 

 in gentle luit effectual movement, so as to separate 

 every leaf, from every other leaf and allow the dry 

 air to get at both sides. 2. The application of a-s 

 much air as can be introduced without blowing the 

 charge out of the machine, a. The skilful adjust- 

 ment of the temperature of that air so as to obtain 

 the highest drying powtr without injury to the pro- 

 duct. — Iiuliaii Tea Uauitr. 



Ascent of the ,Sap.— The precise course follow.'d 

 111 its upward course by the water absorbed by the 

 root has been a matter of controver.sy. Sachs, aud 

 many with him, contend that the sap rises through 

 the walls of the vessels and ducts by a process of 

 imbibition. Others, again, such as Btihrn, Hartig 

 and A esque assert that the fluid does not pass up 

 the sides of the vessels by imbibition as water would 

 pass up a lump of sugar or a piece of sponge, but 

 that it passes upward through the central cavity of 

 the vessel. The matter might be settled if it were 

 possible to seal up all the vessels of a branch with- 

 out 111 any other way obstructing the process of trans- 

 piration. Thus either the branches would wither when 

 the_ vessels were all sealed up, showing that their 

 cavities are the conduits, or they would remain fresh 

 even though the vessels were obstructed, when, of 

 course, the inference would be that the water 

 passed up the side walls, and that the obstruction 

 of the central cavity was unimportant. Profes.sor 

 Errera, of Brus.sels, and liis pupil, M. Laurent, have 

 lately put the matter to the test. They made a 

 mixture of twenty parts of gelatine to 100 of water 

 and added to it a quantity of Indian ink, previous- 

 ly ascertained to have no ill effect on the plant 

 The gelatine melts at 33'0. (<)2°F.), aud remains fluid 

 till the temperature falls to 28= C. (83°F.). A branch 

 of a Vino (Vitis vulpina) attached to the trunk, wed 

 bent so that the base of the curve was pluugas 

 into the melted gelatine at a temperature of 30"— 

 33°C. (say 80=--90--'F.). This done, the branch was 

 severed from the trunk, care being taken to keep 

 the branch, while the cut is made, beneath the 

 gelatine. Under these circumstances it is easy to 

 trace the ascent of the gelatine to a height of from 

 4 to 8 inches. M'hen the branch is cut in the man- 

 ner indicated it is immediately placed in cold water 

 when a small thickness is again cut from the end 

 of the branch, so as to secure contact with the 

 water of a clean .surface in which the gelatine occu. 

 pies the cavity of the vessels, alone without cover- 

 ing the cut ends of the walls of the vessel. All branches 

 111 which the cavity of the vessels is thus blocked 

 wither within a few hours, while test branches, cut like' 

 the others, under water or in air, and treated ex- 

 actly m the .same way except as regards immersion 

 m gelatine, remain uuwithered. If tlie portion of the 

 branch infiltrated and obstructed with gelatine, be cut 

 away, and the freshly cut surface be now immersed 

 in water, it preserves its freshness. From these ex- 

 periments, M. Errera concludes that the "water of 

 transpiration" ascends through the cavities of the ves- 

 sels, and explains in this m.mner the fact that the 

 upward current passes through the portion of the wood 

 formed in spring, and which is marked by vessels of 

 large diameter, rather than through the autumn-formed 

 wood where the vessels are narrower and thicker 

 walled— the latter condition favourable, as it would 

 seem, to imbibition,— Garden^jy Chronicle. 



