332 Quantitative Precipitin Tests 



the Primate bloods only that of a Cynocephalus gave any reaction, and 

 then one of 25 /o, which we cannot explain, having been unable to repeat 

 the test. Possibly the result was due to error. It will be noted however 

 that two cats and a dog, amongst the Garni vora, also gave relatively 

 high figures. 



Tests with Anti-Donkey Serum (8. i. '03). 

 Antiserum from rabbit treated with serum of donkey (929). 



l*recipitum amount 

 Klood of Date 2 tests Percentages 



929 Equus asinus 3. xi. 02 -010 -009 10090 



930 5. xi. 02 -008 '008 8080 

 Equus caballus 17. xii. 02 -009 -009 90-90 



10. vi. 01 -007 -007 7070 



903 Equus grevyi 13. \. 02 -004 -004 4040 



The immediate reaction observed on the addition of anti-donkey 

 serum to donkey blood dilutions was very marked. A faint clouding 

 appeared in the dilution of the more recent horse-blood. After 90 minutes 

 granules and deposit had formed in these solutions, whilst the horse 

 scrum of older date and that of the zebra still showed but a marked 

 clouding. In other words, there was a well-marked sequence in the 

 reaction. 



Parallel Tests with Antisera for Horse, Donkey, and Zebra. 



The anti-horse serum used was taken from two different rabbits 

 (A and B). The anti-donkey serum was a different one from that used 

 in the preceding series. The anti-zebra serum as in the other cases was 

 obtained by treating rabbits with the corresponding serum. The order 

 in which the immediate reactions took place corresponded exactly to 

 the order of precipitum amounts, that is, the dilutions giving the largest 

 amounts of precipitum reacted first, those giving the smallest amounts 

 reacted last. Corresponding appearances were noted after 90 minutes, 

 the precipitum had accumulated entirely at the bottom of the tubes 

 giving the highest precipitum amounts, partially at the bottom and on 

 the walls of the tubes giving lesser reactions, whilst the solutions in the 

 tubes giving the least reactions sometimes only showed a clouding or 

 granulation when deposition was complete in the first of the series. 

 Consequently the rate at which reaction takes place is of value in judging 

 the result. Only two horse-bloods (a, 10. vi. '01 and b, 10. vu. '02), two 



