Mxri; III .MKN'I'S ON (rllM ]' Ki ) I ) |i ( 'Tl (I \ IN I\nl;lMih'AN 



BY 



M. S. MiMK, M.A., r.,S('., Ciinirgic Uosuarrh Krllow, I'.KIS-!) 



On Im'Iii^' awiinlcil ii iciicwal of tlic ( ':iriiOf,'ie Fell()\vslii|i licld li\ iiic iliniii^; IIH)7-8, 

 i discussed witli Dr. Ball'our and J)r. ik-ani the host way in whic'li I nii^^lit be aide to 

 throw some more lif,'lit on tlie sul)jcct of f,'um production, the ))rincii)al questions at issue 

 Ix'in;^' tlie causes alToetiuf;' th{! amount of ;,'imi exuded a,nd the (puiHt}' of thi; gum. It. 

 was (UH'i(h;d that the best way wouhl he foi- nu^ to study the problonis in one of the 

 gum-producing districts, instead of having to get material sent to Khartoum to be worked 

 up there. 



I ai-rived at Taiara, the piincipal centre of tlu; gum inchisti'y in Kordofan, in the 

 first week of Novendjer, IDOH, and was fortunate enough to find that two gum gardens .Scl™tiun 

 suitable for experimental work had l)een ])artly cleared of grass and fenced in by the (.xpcrimcnis 

 Woods and Forests ])e))ailnient in the ])revious season. One gai'deii cdnsistcd enlii-ely of 

 young hashi'ib (Acacia scHecjdl) trees wliieh luiil nevei' been tapped. 'I'hese were all in a 

 good state of healtii and free from accidt^ntal injuries. 'I'iie othei- garden contained 

 principally large trees, pi-oha,hly none Ijeing less tlian ten years old. 



Twenty trees in each of these gardens liad been tap]ie(l in tlie (u-dinary manner before 

 my arrival at Taiara, about October 15. Tt will he of interest to consider the 

 gum produced by these trees before (Altering iiitcj the question of the influence of 

 artificial conditions on the yii^ld of gum. 



(luiii fruiii fn-ciitij .■una/l Ireen. — These trees, tapped for the first time, were among 

 the largest of tliose in the first-iiuMitioned garden, being probably from live to seven 

 years old, judging from ciMiipaiisoii with trees of known ag(^ elsewluire. On tlu' whole 

 they were considerably smaller than the average trees tappi'd by the natives in their 

 own gardens. In order to show the fluctuations in the yield of gum throughout the season, 

 it will be useful to give the, complete figures for these trees, and afterwards to give a similar 

 table in the case of tlu^ large trees. 



It will be seen that tlu; collections, aftcM- tlie first, were made at intervals of about 

 IG days. 



On looking at the table on the next page, one is immediately struck with the enormous Variation 

 variation in yield of tiie individual trees. From an examination of the latter I think '" y*^''' °^ 



... . . individual 



that the variations could not be entirely accounted for by dillerences in the size of the trees 

 trees or the extent of tlu; tapping. Tree No. Id, for cxamiile. was one of tlii; hirgest of 

 these trees, and was as well tapped as any, but yet it only yielded a very small amount 

 of gum. Th(' trees from which only a small amount of gum was obtained may not have 

 been so well infected as the others. 



Of special interest is the amount of gum obtained at the last collection. From the 

 way in which the exudation was gradually falling off, one would have expected very 

 little gum at this time, instead of which not only was there a considerably greater total 

 yield on this occasion than on tlu! one immediately preceding, but several trees actually 

 gave more gum at the last than at any previous collection. The reason for this is probably 

 as follows: — Between March 29 and April 8 about an inch and a quarter of rain fidl, as 

 a result of which many of the smaller trees came into leaf, and the renewed exudation was 



