PRESIDENTIAL ADDRESS — -SECTION C. 55 



with regard to a very large iiuml)er (^f plants we bad. until a few 

 years back, no knowledge as to wbetber they were injurious or 

 innocuous. The Division for Veterinary Research, together 

 with the Division of Botany, have taken the matter in hand in 

 connection with botanical investigations into gal-lamziekte, and 

 have compiled a list of suspected plants, with which feeding and 

 drenching tests were carried out. 1 understand that experi- 

 ments are still in progress, and I have reason to believe that the 

 De]>artment for Veterinary Research would welcome the oppor- 

 tunity of carying out physiological tests with any ])ttre sub- 

 stances isolated from i)lants known or reputed to be injurious 

 to stock. With regard to plants, supposed to be of medicinal 

 value, very little published information alx:)ut authentic tests 

 hv medical men is a\ailable. Apart from buchu and aloes, 

 which are, of cotirse, official, I know only of the publication on 

 Monsonia, the dysentery cure, and the occurrence in it of an 

 oleo-resin, entericin.* And yet I am acquainted with several 

 medical men who. on the streno:th of actual experience, have 

 great faith in some of the native remedies. Possibly their disin- 

 clination to rush into print is due to fear of ostracism by their 

 colleagues for venturing to deviate from orthodox methods and 

 prescriptions. 



In conse(|uence of the cessation of Continental supplies of 

 drugs o;f vegetable origin following on the outbreak of the pre- 

 sent war. attention was directed to other sources of supply in 

 the Dominions and Dependencies. As a profitable source of 

 atropine, or rather the isomeric hyoscyamine. the Datura 

 stramonium (stinkblaar) seems promising. The hyoscyamine 

 content of Hyoscyamus muticus is higher, it is true, than that 

 of Datura stramonium. Bitt according to analyses carried out 

 iit the Imperial Institute! stramonium of South African origin 

 is superior to that from India, Europe, and the Sudan. The 

 report refers only to a small number of samples, and there is no 

 evidence to show that these samples represent the best quality 

 obtainable here. The dilTerent parts of this country are so 

 ditterent witli regard to climate, soil, rainfall, and other essen- 

 tial conditions of plant gn^wth that plants display considerable 

 variations in their toxicity and the amount of active principles 

 they contain. Ornithogalum thyrsoidcs (the chinkerinchee) is 

 undoubtedly extremely poisonous in some districts, whilst in 

 others it is reported to be innocuous, and can be fed to animals 

 without evil effects, C rot on gratissimum. growing in Zululand. 

 is declared to 'be very poisonous, whilst in parts of South- West 

 Africa it is ai)parently a useful fodder plant. Similarly a syste- 

 matic search might reveal the fact that the hyoscyamine content 

 of the stinkblaar in some parts of the country is much higher 

 than that 0(f the specimens reported on. Present prices are 

 abnormal, and cannot be regarded as a criterion, but it seems 



* Maberley. Lancet. 2 (1909), 1363. 



t Bulletin r)f the Imperial Institute. 14 [l], 25. 



