2 PHARMACOPEIAL DRUGS 



instructive recent contributions to acacia literature, is 

 the Report of the Wellcome Research Laboratory, 

 Khartoum, (678), 1904. Even this, however, is excelled 

 in the magnificently illustrated "Third Report" from 

 that institution, presented in 1908, in which we find a 

 fund of information that forbids even summarizing. 

 Pages 414 to 450 present, exhaustively, the subject of 

 gums, whose origin, as might be anticipated, is found 

 due to bacterial infection. The reports are not alto- 

 gether concordant, trees artificially inoculated even 

 falling below the yield by native processes, as shown 

 by the following extract: 



"INOCULATION. In view of the results of Greig 

 Smith's investigations, which appear to prove that 

 gum is formed as the result of infection of the sap 

 by a microbe resident presumably in the bark, and 

 also that extensive removal of the bark is un- 

 desirable, an experiment was carried out as follows: 

 Tapping was performed by making a series of gashes 

 with an axe, no bark being stripped off, and (as the 

 chances of efficient natural inoculation might thus be 

 lessened), an attempt was made to ensure the entrance 

 of the microbe by rubbing a moist rag over the bark 

 and subsequently into the cut. A series of trees tapped 

 in the native fashion (by stripping the bark) was treated 

 in the same manner for comparison. The following 

 table exhibits the results obtained : 



Number of Yield of 



Garden of trees oper- Size of Method of Inoculated gum per 



atedupon trees tapping tree 



AdamAfifi 25 Medium Ordinary Not inoculated 0.9 rotl. 

 25 " Inoculated 0.55 " 



25 " Short 



Gashes Not inoculated 0.28 " 

 25 " " " Inoculated 0.14 " 



