The synergism phenomenon has made possible the recognition of substances, which we have called "prolan-like," in a wide variety of conditions. Indeed, it has been possible to demonstrate a prolan-like material in the urine of normal men.
The method has shown a wide distribution of prolan-like substances in sera and urines of non-primates without demonstrating, however, significant difference in the reactions secured from pregnant as contrasted with non-pregnant states, or in males as contrasted with females.
The synergism phenomenon with pregnancy prolan can also be shown in the increased development of the seminal vesicles of immature male rats. However, such males cannot be advantageously employed in the detection of prolan-like gonadotropic substances occurring in the blood and urine in conditions other than pregnancy, for the prolan-like substances usually do not effect appreciable development of the seminal vesicles.