272 Report S.A.A. Advancement of Science. 



susceptible goats, which in some cases have died of the virulent 

 malady. 



2. That if, after unsuccessful inoculation, they are allowed to 

 remain in the Institute for several weeks, a subsequent intravenous 

 inoculation of virulent blood is almost always successful in pro- 

 ducing the disease and death. 



Kxperimen'.al Observation 10. — To show that goats on farms 

 in this and adjoining areas, reared and living there, are relatively 

 insusceptible. 



I have already referred to the experiences of Messrs. Hoole and 

 White, which suffices as evidence in this respect. 



CO-RELATION OF HORSE SICKNESS TO HEART-WATER, 

 TO VELD-SICKNESS IN CATTLE, AND TO A CONDI- 

 TION KNOWN AS VELD-SICKNESS IN HORSES. 



If horses which have been reared in the Karoo are brought 

 down to the coast areas it is usual to find that they fall off in con- 

 dition, and in some cases die. From what I have heard and seen 

 I am constrained to believe that this condition is that which was 

 referred to in the report of Lieutenant-Colonel Joshua Nunn, 

 F.R.C.V.S., A.V.D., to the Director-General of the Veterinary Depart- 

 ment of H.M. War Office in 1888, as the Biliar}' form of Horse- 

 sickness. Among the farmers it is, however, commonly referred to 

 as Veld-sickness. 



In my communication to the Royal Society (Vol. 67), I referred 

 to the results which I had obtained by the inoculation of donkeys 

 with the blood of animals dying of Horse-sickness, and thereafter 

 using the donkey's blood for the inoculation of horses. 



Since that communication was made I have been able to extend 

 experiments of that class, and the results may be summarised as 

 follows : — 



1. The reaction produced in the donkey is no guide to the 

 result which may follow the inoculation of its blood into a clean 

 horse. The reaction may be slight or may be fatal. 



2. If the donkey's blood is drawn at the tenth day and used to 

 produce in a clean horse a violent reaction, then the blood of the 

 same donkey, if drawn two or three days later (without any further 

 re-inoculation) will cause a much more violent reaction, and possibly 

 death from virulent Horse-sickness. 



3. If a mild reaction is produced it may be of the nature of high 

 temperature with remissions, or if still milder may have a lower 

 degree of fever with long intermissions. 



In the case of animals which suffered from the last form of 

 fever it was always noticed that they fell off in condition to a 

 remarkable extent, becoming mere skeletons. 



If killed or dying as late as the 50th day one found evidence 

 of Horse-sickness in the form of exudation of serous material into 

 the subcutaneous tissues, the interlobular tissue of the lungs, into 



