112 



Mr. A. Edington. 



tional evidence as to the communicability of the disease by the use of 

 blood derived from animals which have been either recovered from the 

 sickness for a very considerable time or which have been inoculated 

 many months previously to the date on which their blood has been used. 



On the 8th December, 1898, I withdrew some blood from animal 

 No. 18, which has been continuously under observation since it was 

 inoculated on the 22nd December, 1897. After defibrinating the 

 blood, 20 c.c. was used to inoculate a young ox (No. 54) by intravenous 

 injection. On the following day a sharp rise of temperature occurred, 

 which reached to 106 - 6 F. On the following morning it was observed to 

 have fallen to 99*8° F. Three days later the temperature was again over 

 104° F., but fell previous to the next morning. From this time onward 

 an erratic course of temperature was observed, and on the twenty-fifth 

 day, subsequent to inoculation, it was seen to be ill, refused food, but had 

 no definite symptoms of " red-water." Three days later it died. The 

 blood on examination was seen to contain the spherical forms of the 

 parasite. 



On post-mortem examination, the bladder and urine were quite 

 normal. The liver was not enlarged, but was somewhat discoloured 

 in patches, and the biliary ducts were distended with bile. The bile 

 was much altered, being stringy and of a greenish-yellow colour. The 

 spleen was normal in size and consistence. The kidneys were enlarged 

 and the pelves were filled up by a yellowish gelatinous exudation. 

 The cortex was somewhat congested, but there was no evidence of any 

 true inflammatory change. The general muscles were pale in colour, 

 and there was slight evidence of jaundice. This experiment serves to 

 show that an animal which has been inoculated with infected blood, 

 while it may not develop much illness as a result of it, is really infected 

 and, moreover, its blood, if drawn as late as a year subsequently, is 

 yet so infective that an intravenous injection of it, into susceptible 



lent when injected into a vein in another animal, it is safely to be inferred that 

 the animal suffering from the mild form becomes more or less immunised or 

 " salted." 



On these grounds I would suggest a method of protective inoculation against red- 

 water in the following manner. Haying procured a healthy animal from a red- 

 water area, or one which is known to have been " salted," inoculate it by injecting 

 5 c.c. of red-water blood into the jugular vein and 5 c.c. subcutaneously. In cases 

 where the operator is unable to attempt the vein inoculation I would recommend 

 the subcutaneous inoculation of 5 c.c. in four different sites. 



Allow at least twenty-eight days to elapse, and if any degree of illness is recog- 

 nised, the blood of this animal may be used, after being defibrinated, to inoculate 

 healthy cattle. For such inoculation only 5 c.c. should be injected into small 

 animals and not more than 10 c.c. into larger. 



Seeing, however, that the presence of other maladies renders such a proceeding 

 unsafe, I would recommend that it should only be practised during the autumn or 

 winter, when the veld diseases are, as a rule, in abeyance, and in no case when any 

 epidemic disease is in the near neighbourhood. 



