Sources of Error 73 



in a rabbit recently treated by Dr Graham-Smith, the opalescence was 

 seen to continue for days, samples of antiserum being taken from the 

 ear- vein so as to test its strength 1 . It would therefore appear desirable 

 to take samples of blood from the rabbits' ear-veins to see if the serum 

 is clear before proceeding to kill the animals. Uhlenhuth states that 

 he has encountered the condition much more frequently in intravenously 

 treated animals, but this has not been our experience here. Uhlenhuth 

 suggests that some of the results of Kister and Wolff, as also of Strube, 

 on non-homologous bloods with different antisera, may receive an 

 explanation from their having used opalescent antisera, their results 

 being contrary to those of about 40 other authors. I am certainly 

 inclined to Uhlenhuth's view on this point. 



Rostoski (19026. p. 29) treated rabbits with different constituents 

 of horse serum, and seems to have encountered the condition rather 

 frequently. This is unfortunate as it necessarily detracts from the 

 value of his results. One rabbit (his No. n.) was treated with the 

 crystallized serum albumen of the horse, yielding an antiserum which 

 was " stark milchig getriibt," and he goes on to say, " doch habe ich 

 gelegentlich auch schon andere milchig getrlibte Sera beobachtet, die 

 nicht eine besondere starke pracipitirende Kraft besassen." Linossier 

 (25, in. 1902) states that he has found anti-human serum to precipitate 

 not only human, but also ox, horse, dog, sheep, guinea-pig, and fowl (!) 

 sera, the reaction, he adds, being however incomparably greater with 

 human blood. He does not state with what concentrations he worked, 

 but says the difficulty can be surmounted by the use of higher dilutions 2 . 

 This is certainly not the case with opalescent antisera. Kister and 

 Wolff (18, XI. 1902) experimenting with anti-horse serum, which had 

 " surprised " them because of the non-specific character of the reactions 

 it gave, tried to see if there were any law with regard to its action on 

 different bloods. These authors expressly state (p. 412) that they only 

 used clear sera, but perhaps they overlooked opalescence which may 

 not be very marked, and which in my experience might deceive one 

 into accepting such antisera. In any case adding it to salt solution 

 would have cleared the matter up. I have referred to their results 

 elsewhere (under tests with anti-horse serum), and it will be seen that 

 they are not in accord with those of the majority of observers, as they 

 obtained quite marked reactions with ox and sheep serum. 



1 Dr Graham-Smith has found several rabbits yielding opalescent antisera to be affected 

 with Cysticerci. This may explain the condition. 

 3 See p. 74. 



