East Coast Fkver. 203 



son and myself in different localities and under different conditions ; 

 but the results obtained were the reverse of encouia<fin*(, and in sub- 

 mittini; a final report on the disease we refrained from recommending; 

 the adoption of any systems of inoculation, advising in its stead the 

 erection of dipping tanks at various points along the main transport 

 roads, where cattle used for transport purposes should be dipped in an 

 arsenical dip once every three weeks, with a view to reducing the 

 number of infecting ticks, and in this way modifying the virulence 

 of the disease. We pointed out that our observations of the micro- 

 scopical character of the disease were identical with those of Prof. 

 Koch as detailed in his 1897 report, and endeavoured to explain the 

 severity of the outbreak by suggesting it might be due to one or to a 

 combination of any of the three under-mentioned causes : — 



(1) To infection with abnormal numbers of pathological ticks. 



(2) To the intensification of the disease by its passage through a 

 large number of susceptible animals. 



(3) To climatic influences, in which case it woukl persist as a 

 constant characteristic of Rhodesian redwater. 



Ill concluding our report we gave it as our opinion that the 

 epidemic differed from previously recorded epidemics in the following 

 respects : — 



(1) In the severity of the infection and mortalitv amongst infected 

 herds. 



(2) In the fact that young animals bred and i-un on infected veld 

 contracted the disease and died. 



(3) In the fact tliat one attack of the disease did not confei' any 

 lengthy immunity. (This we afterwards found was not the case.) 



(4) The severity of the pi»st mortem lesions. 



(5) The presence of lung lesions in 30 per cent., and of kidney and 

 lung infarcts in the greater proportion of cases. 



(6) The uncertainty of conferring immunitv in clean stock l)y the 

 methods of ijioculation practised in Cape Colony and America. 



We concluded by expressing our belief that the \irulence of the 

 disease would probably abate at a later stage. 



The views then expressed by us at this time as to the character of 

 the flisease were indorsed both by Dr. Hutcheon, late chief veterinary 

 surgeon. Cape Colony, and by Mr. Watkins Pitchford, Government 

 veterinaiy bacteriologist, Natal, both of whom visited .Salisbury while 

 these insestigations were proceeding. Shortly aftei- the publication of 

 this report Mr. Robert.son was recalled to resume his duties in Cape 

 Colony, while I remained in Rhodesia to note the result of our 

 recommendations. 



Unfortunately our anticipations were not realised. Dipping difl 

 not seem to check the spread oi. the disease, for the simple reason that 

 although the dips used destroyed the ticks on the animals at the time 

 of dipping, they did not prevent tliem becfuning reinfested in the 

 course of a few days. The mortality increased steadily, and the disea.se 

 extended along the transport routes to almost every district in Rhodesia, 

 with the exception, perhaps, of the Mangwe district, and as it showed 



