176 Tests ivlfh Frecijntins 



(see tables), which acted peculiarly with other antisera. The other 

 rodent blood giving this slight reaction was No. 283, and no explanation 

 can be offered for the result. 



(3) Tests with Anti-Dog Sera. 



Nolf (v. 1900) first produced anti-dog serum by treating rabbits 

 with dog serum. He was unsuccessful when he treated them 

 with dog blood corpuscles. The antiserum did not precipitate some 

 other bloods tested. In my note of 11, v. 1901 I reported having 

 obtained negative results with 23 bloods other than dog's. Similar 

 results have been obtained by Uhlenhuth, who found the anti-serum to 

 react with the blood of the fox. In my paper of 21, xi. 1901 I reported 

 having only obtained reactions with the bloods of six species of 

 Canidae, 196 non-canine bloods having given a negative result. By 

 reference to the tables, it will be seen that a considerably larger 

 number of canine bloods has since been examined. Gengou (25, X. 1902, 

 p. 751) tested this antiserum upon four bloods (dog, horse, ox, guinea- 

 pig) and found only that of the dog to react. 



I will add here that Uhlenhuth (25, vii. 1901) has produced an 

 anti-fox serum, which, tested on 24 bloods (see his list, p. 172) only 

 reacted with the blood of the fox and dog, less Avith the latter. 



Farnum (28, xii. 1901) prepared anti-dog serum and found it to 

 precipitate solutions of serum of the dog, but not of man and bull. 



777 Tests with Anti-Dor/ Serum. 



These tests were carried out in the course of two years and necessi- 

 tated the use of five different antisera obtained from as many rabbits 

 which were treated with the serum of Canis familiaris (different 

 breeds). Four of the sera were powerful, one weak. The weak anti- 

 serum was scarcely used. One of the powerful sera (the last used) 

 was standardized, being found to give a precipitum of "015 c.c. 



We see from the following table that the dogs form a detached group 

 amongst the Camivora, for with the exception of one of the Mustelidae, 

 no other bloods gave a full reaction. Three canine bloods gave 

 negative or faint reactions, the two giving negative results were sent 

 from India (196) and South America (204), the one giving a faint 

 clouding only, from India (187). It may therefore be assumed that 

 these bloods had become relatively insoluble. The proportion of medium, 



