The Abderhalden Reaction 133 



which have been enumerated should have decided the ques- 

 tion long before. 



12. The Abderhalden Reaction 



Abderhalden (^) announced in 1912 the discovery of a 

 highly interesting method for diagnosing pregnancy by a 

 laboratory test. A test fluid is made from placental tissues, 

 to which is added serum from the animal to be tested, and 

 the mixture is placed in a dialyzing tube. If the animal is 

 pregnant, portions of the ferments existing within the blood 

 serum dialyze into surrounding distilled water, in which 

 they may be recognized by a delicate purple coloring, upon 

 the addition of ninhydrin followed by heat. It is claimed 

 that the placental ferments appear in the blood as early as 

 eight days after conception and disappear within fourteen 

 to twenty-one days after the expulsion of the placenta. In 

 the larger domestic animals it is more than eight days be- 

 fore any placental tissue commences to form. It is not easy 

 to understand how a test for placental elements can act until 

 placental tissues exist. The statement that a reaction may 

 occur as early as at eight days is probably based upon re- 

 searches upon some small rodent, where the- placenta de- 

 velops much earlier. 



Since the preparation of the test material and the test it- 

 self are very complex, requiring delicate laboratory appara- 

 tus and highly technical skill, the test is expensive as com- 

 pared to its value in the veterinary field. Even in human 

 obstetrics and gynecology, where the cost is not as great 

 an element and where an accurate physical examination is 

 not nearly as practicable as in the mare and cow, the test 

 is not regarded by many of the foremost authorities as effi- 

 cient. J. Whitridge Will'iams(^) states, "While I consider 

 that the method should be regarded as one of the important 

 recent contributions to medicine, I do not believe that it is 

 destined to come into extensive practical use for several 

 reasons : First, its technic is so complicated that it can be 



1 Die Serodiagnostik der Schwangerschaft, Deutsche med. Wochenschr., 

 1912, No. 46. 



' Obstetrics, 1917. 



