Report of the Department of Agriculture. 533 



Other Toxic Plants. — All throiioh the year toxicity tests were 

 carried out with gifhlaar (Dichapeialum cijtpnxnm). An explanation 

 wns found for the earlier contradictory results. It was proved that 

 only the young' leaves are toxic. In the spring cases of poisoning are, 

 therefore, most numerous, but later in the season, when most of the 

 leaves Lave matured and lost their toxicity, a new batch of young- 

 leaves appears which again proved to be very poisonous. Numerous 

 feeding experiments were conducted with suspected plants that were 

 sent in by farmers and others and were reported to be injurious tO' 

 stock. In practically every iiistance, the result of the feeding- test 

 at the Inboratory was ]iegative. 



Miscellaneous. — Various otiier diseases were investigated during 

 the year, but in most cases no definite concdusions were arrived at. 

 Amongst these diseases may be mentioned the so-called Sireafing 

 Sickness in Calt^es, a disease which was first reported from Rhodesia 

 a few years ago, and has since made its appearance in several other 

 5)arts of South Africa. An officer of this Division made a preliminary 

 investigation into the disease in vSwaziland, where it is rapidly 

 spreading, but in the absence of proper facilities, satisfactory experi- 

 ments could not be conducted to clear up the nature of the condition. 

 The investigations are being continued. 



A peculiar disease in sheep with exudative inflammation of the 

 skin leading to extensive formation of crusts was brought to the notice 

 of the Division. A few sheep were sent to the laboratory, and 

 among\st them oir3 or two cases of paralysis of the hind quarters 

 appeared. In these cases a degeneration of certain portions of the 

 spinal cord was observed. This clue will be followed up as soon as 

 moi'e jnaterial can be obtained. 



Preliminary investigations were also conducted on Blue Udder 

 in sheep. This is a disease tiiat has been described in Europe. Fortu- 

 nately, it seems as if it is less virulent in South Africa than in 

 Europe. Organisms were isolated from the diseased udder, and with 

 them a somewhat similar condition was reproduced in experimental 

 sheep. However, further work is necessary before any of these organ- 

 isms can definitely be iiu'riminated as the cause of the disease, and 

 before therapeutic experiments can be commenced. 



A condition jn lambs known as AplitTia was also examined. 

 Farmers have expressed the opinion that the disease is transmitted 

 by means of flies. From the preliminary observations, it seems not 

 unlikely that more than one distinct disease in lambs have been 

 grouped under this name. The true aphtha is probably non-fatal ; the 

 cases of death in the same flock being' most likely due to another 

 cause. 



Biochemical and physiological investigations into lamsiekte and 

 other diseases are under consideration, including general veterinary 

 dietetics ; investigations into compounds of probable value in the 

 destruction of external parasites of stock; studies of " rapid methods" 

 for the determination of ingTedients used in commercial dips ; further 

 experiments on dipping; influence of phenolic bodies upon bacterial 

 changes in dipping tanks ; improvements in methods for field assay o£ 

 dip washes ; and development of biochemical methods lor clinical use 

 in veterinary medicine. 



