Abstract
Comparisons have been made of the rotatory power and copper reducing power of ultrafiltrates from normal beef and rabbit plasma. The technique of ultrafiltration was essentially that of Marshall and Vickers. 1 The filtrates, without further treatment, were observed in a Schmidt-Haensch triple field polariscope with scale graduated to 0.01 degree. The first readings were made within four or five hours after drawing the blood. The readings were repeated on succeeding days. The copper reducing power was determined by the method of Shaffer and Hartmann. The reducing power remained constant for several days. Bacterial action was prevented by addition of toluene.
The experiments are divided into three groups:
1. The plasma was filtered directly with no preliminary treatment.
2. The plasma was acidified with eight drops of glacial acetic acid per 100 cc. before filtration.
3. The plasma was partially precipitated with small volumes of 20 per cent sodium tungstate and 1.3 N sulfuric acid before filtration.
The results of a few typical experiments are shown in Table I. The sixth column of the table shows the rotation calculated from the reducing power assuming the specific rotation + 52.5°.
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