Scientific Proceedings (67). 



plasma, previously freed from C0 2 gas in a vacuum, gives a 

 practically neutral solution {P H = 7.0). Plasma from patients 

 in acidosis has been observed to give a P H = 4.8 under the same 

 conditions. The results by this method run parallel to those by 

 the C0 2 capacity method, and both blood analyses give figures 

 from which the alveolar C0 2 tension can be predicted within 

 about 5 mm. 



The above results indicate that while in acidosis the H+ 

 concentration of the blood is not altered, its reserve alkalinity 

 (ability to retain normal reaction despite addition of acid) is 

 decreased, and that the decrease can be measured by any of the 

 above three methods. 



100 (1032) 

 The Abderhalden reaction II. 

 By Donald D. Van Slyke, Miriam Vinograd and J. R. Losee. 



[From the Rockefeller Institute and the Lying-in Hospital, New York.] 



The technique described in the Proceedings for May 20, 

 1914, has been modified to the following, which permits more 

 accurate determination of small differences in proteolysis as 

 measured by the amino acid nitrogen: 0.1 gram of dried placenta 

 substrate, or an approximate equivalent of wet substrate, prepared 

 according to Abderhalden, is incubated with 2 c.c. of serum. The 

 mixture is then diluted with about 20 c.c. of water, heated to 

 boiling, and Merck's dialyzed ferric hydrate (Rona-Michaelis 

 method) is added, 1 c.c. for serum alone, 2 c.c. for serum and 

 substrate. The excess iron is precipitated by adding 0.5 c.c. of 

 I : 1 solution of crystalline MgS0 4 , and the solution is filtered 

 and washed into a small evaporating dish. The solution is con- 

 centrated on the water bath to dryness; the residue is redissolved 

 in a few drops of water, and washed completely into the micro- 

 amino-nitrogen apparatus. Serum alone gives 0.18 to 0.28 c.c. 

 of nitrogen gas, duplicates on the same serum agreeing within 0.01 

 c.c. or closer. The increase due to placenta may be as high as 

 0.25 c.c. Normal male sera give results varying over about the 

 same range as pregnant sera, although a somewhat greater pro- 

 portion of pregnant than of male sera give results near the upper 

 limit of the range. 



