Live Stock. 



424 



[May, 1912. 



shipped, probably stop a good and pay- can be used to make those who do not 

 ing industry. Steps should be taken to protect their own crops abate their 

 protect the industrious, clean culture nuisance, and thereby check the pro- 

 practising grower by regulations which miscuous breeding of all kinds of pests. 



LIVE STOCK. 



PLANT POISONS. 



By Joseph Burtt-Davy, f.l.s., f.r.g.s., 

 Government Botanist, Transvaal. 



(Prom the Agricultural Journal of the 

 Union of South Africa, Vol. III., 

 No. 1, January, 1912.) 



The losses among stock in South Africa 

 due to poisonous plants have not received 

 that attention which the subject de- 

 serves, owing to the fact that hitberto 

 efforts have been largely concentrated 

 upon tick-borne and other diseases duo 

 to parasites. Now that these parasitic 

 diseases are in a measure under control, 

 stock farmers aie turning their attention 

 to other sources of loss among their 

 flocks and herds, such as lack of winter 

 feed and direct loss from eating poison- 

 ous plants. The recent ravages of 

 " gal-lamziekte " in Bechuanaland and 

 the adjacent districts of the Transvaal 

 and Orange Free State, a disease which 

 appears to be caused by some obscure 

 poisonous plant, have brought the sub- 

 ject prominently before the public. 



I do not propose to discuss gal-lam- 

 ziekte in the present article, as a joint 

 report on the subject by Dr. Theiler 

 and myself is in course of preparation. 

 But in order to secure the intelligent 

 assistance of stock farmers in clearing 

 up the problems connected with poison- 

 ous plants, I have prepared the follow- 

 ing preliminary notes on plant poisoning. 

 I shall be glad to receive from farmers 

 throughout South Africa, and especially 

 in the gal-lamziekte area, specimens of 

 any of the grasses, bushes, or " weeds" 

 which are eaten by stock, and of any 

 plants which are suspected of being 

 poisonous ; these can be sent post free 

 if marked "O.H.M.S.", and addressed— 

 "The Government Botanist, 

 P. O. Box 434, 



Pretoria." 



In discussing gal-lamziekte many farm- 

 ers have expressed the opinion that 

 the disease is caused by some poisonous 

 plant. Others have thought this im- 

 probable, or even impossible, because 

 of certain peculiarities connected with 

 the incidence of the disease. A study 

 of plant poisoning in different parts of 

 the world explains some of these pe- 

 culiarities, which are quite compatible 

 with the known characteristics of poison- 

 ing by certain plants, as can be seen 

 from the following notes :— 



Season of the Year. — With some poison- 

 ous plants trouble is experienced mainly 

 at certain seasons of the year ; this is 

 particularly the case with the Tulps 

 (species of Homeria and Moreno) and 

 Slangkop (Urginea, Burkei), and usually 

 also with Chailletia or Gift-blaar (Di- 

 chapetalum cymosum.) In these cases 

 the reason may be traced to the fact 

 that the plants in question make their 

 new growth of foliage before the rains 

 begin, and therefore at a time when green 

 feed is scarce and stock are suffering 

 from a prolonged diet of dry food. 

 They pick up the poisonous foliage in 

 their eagerness for something green, 

 either in ignorance of its poisonous 

 character, or accidentally among the 

 short grass just springing. Such plants 

 are usually avoided by animals accus- 

 tomed to them. But with other poison- 

 ous plan ts the case is sometimes quite 

 different. 



In veterinary practice it is commonly 

 recognized that a plant may be harmful 

 at one time and net at another. It is 

 well known that vegetable drugs differ 

 in potency at different seasons of the 

 year, the difference being, perhaps, cor- 

 related with the stage of growth of the 

 plant. Some are only officinal if gathered 

 at a particular season or stage of de- 

 velopment. That a similar difference 



