DEPARTMENT OF GENETICS. 113 



Miss E. E. Jones, has made an analysis of the records in the Stud Books of 

 the American Kennel Club. The necessary tabulations and calculations have 

 been made and the material is now ready for publication. 



Heredity op Blood Types in Mice; a Negative Result. 



As is well known, human blood falls into a number of types which differ 

 by the capacity of the serum to agglutinate the corpuscles. Obviously a 

 person's own blood will not agglutinate his corpuscles and thus destroy the 

 functioning of the blood. Also the blood-serum of A's own blood type will 

 not agglutinate the corpuscles of A's type. But there are other types which 

 probably will. Von Dungern and Hirschfield abroad and Ottenberg in this 

 country have maintained that these types are inherited simply, and indeed in 

 Mendelian fashion. Others dispute this conclusion. It was thought desir- 

 able to test the theory in a rapidly breeding animal whose breeding could be 

 controlled. It was stated that blood groups similar to the human occurred 

 in rabbits and cattle. It was decided to look for them in mice, especially 

 since the numerous collaborators working on mice at this Department during 

 the summer would bring together a great variety of strains. Accordingly, 

 the necessary technique was worked up by Dr. MacDowell in preparation for 

 the testing of the various stocks of mice for isoagglutinins that might appear 

 in regular groups. 



From 11 different races of mice contributed by Drs. Little, Dunn, and 

 Strong, Professor Gates, and Miss Vicari, 48 sera were made and a total of 

 300 samples of cells were tested; the total number of different combinations of 

 cells and sera was 1,180. Of these combinations, 2 showed agglutinations. 

 Repeated tests with sera from the same stock and cells from the same mice 

 failed to substantiate these positive findings. 



Since one mouse yields such a small amount of serum, it was thought that 

 some other serum, obtainable in larger quantities, would be far more satis- 

 factory as a test for differences in the bloods of different strains. To this end 

 4 guinea-pig sera were used in making 180 tests; 4 sheep sera were used in 

 making 136 tests; and 9 rat sera were used in making 275 tests. In every 

 case the guinea-pig and the sheep sera showed unquestionable agglutination, 

 and in no case did the rat serum show any signs of agglutination, although 

 the whole range of stocks Was represented in all three cases. 



Our attempt to study the heredity of blood groups in mice has thus ended, 



since there apparently are no blood groups in mice. All we found was that 



mouse cells are agglutinated by the serum of guinea-pigs and sheep, but not 



of rats. 



Susceptibility to Inoculate Tumors. 



The work on inoculable tumors, which was reported on at some length in the 

 Year Book for 1921, pages 122-127, has been continued by Doctors Little and 

 L. C. Strong, and by the use of larger numbers of individuals the Mendelian 

 behavior of the factors underlying susceptibility to the two adeno-carcinomas 

 dbrA and dbrB has been more clearly established. 



In the F 2 generation susceptibility to the dbrB tumor depends on the 

 presence of at least two independent Mendelian units, since a typical 9 : 7 

 ratio is obtained in this generation. The susceptibility factors are called 

 A 8t and B 3t . For the dbrA tumor, 3 Mendelian units are necessary. Of these, 



