Inheritance of Susceptibility. 



163 



of about the same quantity, after which complete analytical data 

 and a detailed account of the preparation will be published 

 elsewhere. 



When the composition and properties of the amino acid are 

 definitely established, it will be necessary to show that it is really 

 a primary component of protein. It is possible that the sulphur 

 has been introduced into the molecule either from the sulphuric 

 acid used in hydrolysis, or from the H 2 S used throughout the 

 preparation. The possibility of introducing sulphur from sul- 

 phuric acid is rather remote, since the amino acid has not the 

 properties of a sulphonic acid. However, it can be excluded only 

 by the use of enzyme digestion or alkali hydrolysis in the primary 

 breaking down of the protein, and this has not yet been attempted. 

 In the preparation as outlined above, it is apparently not possible 

 to avoid the use of H 2 S, and this factor can be ruled out only by 

 the elaboration of a method based on quite different principles, or 

 by careful quantitative determinations of total sulphur throughout 

 the various fractions, which is not likely to prove very satisfactory. 

 It is not apparent, however, just how sulphur from H 2 S could be 

 introduced into any of the known amino acids to give a compound 

 of the above formula. 



Should it be possible to exclude these sources of extraneous 

 sulphur, this compound will probably account for a part at least 

 of the non lead-blackening sulphur known to be present in certain 

 proteins. The amount present may well be considerably in excess 

 of the present yield, since the method is obviously not quantitative. 



76 (1823) 



The inheritance of susceptibility to implants of splenic tissue in 



mice. 



1. Japanese waltzing mice, albinos, and their Fi generation 



hybrids. 



By C. C. LITTLE and B. W. JOHNSON. 



[From the Carnegie Institution oj Washington, 

 Cold Spring Harbor, N. FJ 



The use of the terms "auto," "homio," and "hetero" trans- 

 plantation has been general and of great value in the long series 



