Tonicity in Human Isohemagglutination. 



15 



by ordinary absorption methods, but also by working with an 

 " agglutinin " bound to the cells and then split off by heat to 

 50 0 C. (Landsteiner). Such a "bound agglutinin" is highly 

 "specific" ; that is, if it has been bound by cells of group II it 

 agglutinates only members of group II and not members of group 

 III. Such an apparent demonstration of multiple specific agglu- 

 tinins does not, however, rule out simple tonicity as the sole cause 

 of the isoagglutination, for it may be shown that when serum I 

 has been absorbed by blood II, the tonicity of the serum has 

 changed to equal the tonicity of II. Such an absorbed serum 

 would naturally no longer agglutinate II, but would still agglu- 

 tinate III, since serum II will agglutinate III. 



There is strong evidence, then, for the belief that isoagglutin- 

 ation of human blood may be due simply to physico-chemical vari- 

 ations in molecular concentration, and may be independent of the 

 presence of any hypothetical new chemical bodies (agglutinins). 



7 (263) 



Effects of calcium and magnesium salts upon the development 



of rigor mortis. 



By S. J. MELTZER and JOHN AUER. 



[From the Department of Physiology and Pharmacology of the 

 Rockefeller Institute for Medical Research.'] 



The effects of calcium and magnesium salts were studied on 

 rabbits, cats, guinea pigs, rats and frogs ; most extensively, how- 

 ever, on rabbits. Effects were obtained by means of subcutane- 

 ous, intravenous or intra-arterial injections ; the intravenous method 

 being more extensively employed than the other methods. The 

 infusions were given in solutions of M/i, M/2, M/4, or M/8 con- 

 centration. Of the calcium salts we used CaCl 2 , Ca(N0 3 ) 2 and 

 Ca(C 2 H 3 0 2 ) 2 ; of the magnesium salts, MgS0 4 , MgCl 2 , Mg(N0 3 ) 2 

 and Mg(C 2 H 3 0 2 ) 2 . 



The following are the chief results. Calcium salts hasten and 

 magnesium salts retard the development of the rigor of skeletal 

 muscles. After treatment with calcium salts the rigor may begin 

 twenty minutes after death, and after magnesium treatment it may 



