Ant i- Rodent Sera 179 



a precipituni. Two years ago I sought to discover if isoprecipitins 

 were formed in rabbits treated with the serum of other rabbits, but the 

 result was negative, and I have not mentioned it hitherto. Hamburger 

 (6, XI. 1902, p. 1189, footnote) states that he obtained negative results 

 in treating guinea-pigs with rabbit serum, consequently Gengou's state- 

 ment requires further confirmation before it can be accepted. On the 

 other hand Hamburger reports that ho has succeeded in obtaining 

 anti-rabbit serum by treating a goat with rabbit serum. De Lisle 

 (xi. 1902, p. 399) states that he has obtained anti-rabbit serum by 

 injecting rabbit blood into eels. Haemolysins were also formed in the 

 eel, so that its serum after treatment was four times as toxic for rabbits 

 as before. He does not state the strength of the blood dilutions he 

 tested, nor is there mention of control tests on other sera, consequently 

 his precipitin results are not as valuable as they might be. 



I have only had time to make two attempts to obtain anti-rabbit 

 sera. Following Nolf, I used a fowl and duck for treatment, but in 

 neither case was I successful. Working with birds is not satisfactory in 

 any case, as compared to mammals. The goat would appear to be the 

 most likely animal for such purposes. I regret not to be able to give 

 a series of tests with an anti-rodent serum at present, but shall perhaps 

 have an opportunity of doing so later. It will be very interesting to 

 see how the collection of rodent bloods will behave to such an anti- 

 serum. On glancing through the tables, we see that the results are 

 throughout practically^ negative with rodent bloods. Here and there a 

 rodent blood reacts, but this can be put down in some cases to experi- 

 mental error. Also where the most powerful anti-mammalian sera were 

 used, we see a number of slight cloudings noted (anti-pig, anti-human, 

 anti-hyaena) but they appear to have no significance excepting as slight 

 indications of mammalian relationship. I would surmise that a powerful 

 anti-rodent serum might possess a very generalized action in this group. 



V. Antisera for Bloods of Ungulata. 



a. Suidae. 



(1) Tests with Anti-Pig Serum. 



The first to produce anti-pig serum was Uhlenhuth (25, vii. 1901) 

 who tested 24 bloods therewith (see list on p. 172); the only bloods ho 

 found to react were those of the pig and wild-boar. I subsequently 

 (20, I. 1902) tested 250 bloods with this antiserum, with the result that 



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