continuing on many farms where vaccination was carried out. 

 Whether the theory that the disease is carried by Hippoboscids can 

 be supported by direct experimental evidence remains to be proved. 

 Observations in other countries indicate the possibility of flies being 

 vectors of the disease [R.A.E., B., ii, 73, 169 ; vi, 181], and it is suggested 

 that further investigations should be made regarding its local and 

 seasonal prevalence and its relation to climatic and other conditions 

 favouring the insects concerned. 



Mitchell (D. T.). The Effects of Arsenite of Soda Dipping Fluids on 

 Working Oxen.— Union S. Africa Dept. Agric, 5th and 6th 

 Reps. Direc. Vet. Research, April 1918, Pretoria, 1919, pp. 553-591. 

 [Eeceived 13th November 1919.] 



The regular dipping of cattle in sodium arsenite solutions, which 

 has become general throughout South Africa, is found to produce a 

 detrimental effect upon working oxen. The absorption of the solution 

 through the skin causes considerable interruption with the respiratory 

 mechanism, giving rise to laboured breathing and profuse sweating 

 when the animals are put to strenuous work. It has been noticed that 

 animals that have been dipped regularly when young acquire a certani 

 tolerance, which becomes more pronounced as they grow older. 

 Climatic conditions also exert a marked influence, hot, windless days 

 producing the most detrimental effect. The most marked symptoms 

 occur a day or two after dipping has taken place. 



A number of experiments were undertaken, which are described. 

 These show that, given a tank with a sufficiently long swim and dipping 

 at five-day intervals, it is possible to prevent tick infestation with a 

 dipping fluid containing only "128 per cent, arsenic, instead of the 

 standard '16, and that this is the maximum strength that can be used 

 on oxen without producing a degree of respiratory distress incompatible 

 with good work. 



Geeen (H. H.). Isolation and Description of a Bacterium causing 

 Oxidation of Arsenite to Arsenate in Cattle Dipping Baths.— 



Union S. Africa Dept. Agric, oth and 6th Repts. Direc. Vet. 

 Research, April 1918, Pretoria, 1919, pp. 595-610. [Received 

 13th November 1919.] 



An apparently new organism. Bacterium arsenoxydans, has been 

 isolated from the cattle-dipping tank at Onderstepoort. It is the 

 causal agent of deterioration in arsenical dips and appears to be the 

 only one to which rapid oxidation is to be ascribed. The same organism 

 has been detected in mixed cattle and horse faeces. Its characteristics 

 are largely negative ; it is differentiated from most of the commoner 

 organisms by its high tolerance for arsenite. Oxidation proceeds 

 slowly in concentrations as high as 0-8 per cent., the rate of oxidation 

 under suitable conditions increasing as the concentration of arsenite 

 decreases. A faintly alkaUne medium produces most rapid oxidation, 

 while slight acidity inhibits the process. Although the organism does 

 not grow under anaerobic conditions in bouillon, growth readily occurs 

 in the presence of nitrate. 



