TVVENTV-FIVE YEARS OF CHEMICAL INVESTIGATIOX. lOI 



markets (provided it can be found in sufficient quantity) for the 

 reason that it contains twice as much cantharidin as the latter. 

 He goes on to observe: — 



" This Mylabris yields 2.09 per cent, of cantharidin, accompanied 

 with only 10-45 per cent, of extractive, while the Spanish Cantharis 

 produces only .42 per cent- (of cantharidin) and the more troublesome 

 amount of 18 per cent- of extractive." 



In this connection a rather curious result followed an in- 

 vestigation by Mr. Muller in the Grahamstown laboratory during 

 1909. An analysis of the Mylabris which he made showed even 

 better results than those quoted by Smith, for with practically 

 the same amount of cantharidin — nearly two per cent. — there 

 was only seven per cent, of extractive matter, but the remaricable 

 feature consisted in the fact that the stomach and other viscera 

 of a man, who had obviously been poisoned by an administration 

 of powdered Mylabris, contained no trace of cantharidin, although 

 fragments of the insect's wing cases were clearly present. 



One incidental remark before another branch of investigation 

 is considered. During the nine years 1902- 1910, inclusive of 

 cases of poisoning, the Cape laboratories investigated no less 

 than 259 chemico-legal cases in all. These, looked at super- 

 ficially, may be truly spoken of as " routine work." and in many 

 cases no new features could be expected, yet they v^ere worth 

 undertaking — from the point of view of scientific progress — 

 because without this branch of work the interesting steps above 

 recorded in connection with the country's plant poisons would 

 never have been taken. 



Soils. 



Here I pass on to another phase of our investigational work 

 — a phase which I have brought so prominently before the public 

 in various ways during several years past that my words con- 

 cerning it on this occasion shall — relatively to its importance — 

 be few. I refer to the investigation of the country's agricultural 

 soils. With this class of investigation my official connection 

 with the Cape Government may be said to have begun, for my 

 first report to Government was dated the 30th October, 1886, 

 and it comprised the results of analyses of twenty-nine repre- 

 sentative tobacco soils of the Cape Colony from the Divisions 

 of Tulbagh, Ceres, Worcester, Malmesbury, Swellendam, Heidel- 

 berg, Riversdale, George and Oudtshoorn. The Government had 

 then no laboratory of its own, and by favour of the South African 

 College Council and Professor Hahn, the investigation was con- 

 ducted in the chemical laboratory of that institution. Since 

 then, as already stated, over 1,100 soils have been analysed in 

 the Government's own laboratories, and the results of these series 

 of soil investigations have been published by me in the form 

 of a royal 8vo volume of 221 pages. In that volume I reiterated 

 the lamentation to which I had previously given utterance in my 

 pamphlet on " The Underground Waters of the Colony," and 

 in that on " South African Pharmacology," viz., that investiga- 

 tion in each of these three respects had not been ampler and 



