ABDERHALDEN'S SERODIAGNOSIS OF PREGNANCY 267 



:,, 



be conducted in a special room, where there is no dust or fumes of acids, 



and where no bacteriologic work is in progress. This observer also 



recommends that a special incubator be used for this work. If, however, 



the working table is scrupulously 



clean and the glassware is clean and 



sterile, and if the shells are handled 



with sterile forceps and the dialyzing 



cylinder is stoppered with a plug of 



sterile cotton, all requirements are 



practically fulfilled. 



Reagents. The presence of albu- 

 min or its split products may be 

 detected by two color reactions: (1) 

 the biuret reaction, and (2) the nin- 

 hydrin reaction. The first is espe- 

 cially delicate for uncleaved albumin, 

 and the latter for peptones and amino- 

 acids. The technic of the biuret test 

 is described with the technic of testing 

 shells for permeability to albumins. 



Ninhydrin. This is the trade 

 name for triketohydrindenhydrate. 

 It is a whitish yellow, readily soluble 

 powder, dispensed in brown glass 

 vials containing 0.1 gram of the drug. 

 A circular describing its method of 

 use accompanies each package. As 

 0.2 c.c. of a 1 per cent, watery solu- 

 tion is the amount necessary for a 

 test, the contents of the vial are dis- 

 solved in 10 c.c. of distilled water, 

 and the vial rinsed with a portion/ 

 of the solvent. This solution should 



be preserved in a brown bottle in a cold place, and precautions taken 

 to prevent infection. Triketohydrindenhydrate has been described by 

 Ruheman, 1 who gives its formula as follows: 



/CO 



FIG. 76. A DIALYZING CYLINDER 

 FOR THE ABDERHALDEN FERMENT 

 TEST. 



The shell contains placental 

 tissue and fresh serum; it is sur- 

 rounded with 20 c.c. of distilled water 

 and covered with toluol. The cotton 

 plug prevents contamination. The 

 cylinder is readily sterilized in a hot- 

 air oven and affords a simple and 

 efficient means for conducting the 

 test by the dialyzation method. 



C 6 H 4 



;C(OH) 2 



1 Jour. Chem. Soc., London, 1910, xcvii, 2025. 



