Anti-Fowl Serum 201 



African ostrich. What I have termed a ' marked clouding ' is probably 

 to be regarded as an indication of a more remote relationship." Anti- 

 fowl serum produced a slight cloud in only one mammalian blood of 

 those tested, this being put down to some experimental error, the 

 sample having been sent me from abroad. It may have been collected 

 carelessly, viz. brought in contact with avian blood collected on the same 

 day when out shooting. These results are incorporated in the following 

 table. Subsequently (5, iv. 1902) I succeeded in obtaining an anti- 

 ostrich serum, the tests with which follow those with anti-fowl serum. 



It is interesting to note that but a slight action is exerted by anti- 

 fowl serum upon fowl egg-white dilutions, compared to a very powerful 

 action upon fowl blood. Gengou (25, x. 1902, p. 753) notes that this 

 antiserum acts on fowl egg-white, but does not record the remarkable 

 difference in the amount of the reaction, which I have repeatedly ob- 

 served. A fairly powerful antiserum may in fact give no reaction with 

 its corresponding egg-white. 



792 Tests with Anti-Fowl Serum. 



The following tests were made with two antisera obtained from two 

 rabbits treated with the serum of Gallus domesticus. Both antisera 

 were very powerful, giving, when standardized, the one a precipitum 

 of '05 c.c. with "5 c.c. of a 1 : 40 fowl serum dilution, the other a pre- 

 cipitum of '035 c.c., with '5 c.c. of a 1 : 100 dilution. 



The following table shows a strikingdifference from all of the preceding, 

 and a great resemblance to the succeeding one with anti-ostrich serum. 

 We see here an absence of reactions outside of the bloods of Aves, all 

 of which react, whether they be of Ratitae or of Carinatae. Footnotes 

 refer to some of the bloods which gave negative results. It is evident 

 that not much importance can be attached to these when other bloods 

 belonging to the same family have given even the largest reactions. 

 It will be noted that the egg-white of the fowl, whose serum was used 

 for treating a rabbit, gave a much smaller reaction than did the fowl's 

 blood. Note that Galliformes gave 27 %, Anserifonnes 26 %, of the 

 largest reactions in their respective families. 



