TESTS FOR PREGNANCY 927 



nancy urine into mice and rats and, later, observing the appearance of hemor- 

 rhagic conditions of the foHicles within the ovaries. A modification of the 

 Aschheim-Zondek or A-Z test used by Kupperman, Greenblatt, and Noback, 

 '43, consists of the injection of 1.5 cc. of a morning sample of urine into the 

 lower portion of the abdomen of immature rats. The animal is killed with 

 ether after two hours and pronounced hyperemic conditions of the ovary are 

 observed as a positive test. 



2. Friedman Modification of the Aschheim-Zondek Test 



In this test 10 cc. of the suspected urine is injected into the marginal vein 

 of the rabbit's ear. In about 12 to 24 hours a positive test is denoted by ovula- 

 tion points (blood points) on the ovarian surface and by hemorrhagic con- 

 ditions within the follicles. This test is as accurate as the original A-Z test 

 and works in almost 98 to 99 per cent of the cases. 



3. Toad Test 



When the "clawed toad" of South Africa, Xenopus laevis, is injected with 

 pregnancy urine, the animal ovulates within a few hours and the eggs are 

 easily detected. 



4. Frog Test 



Wiltberger and Miller, '48, advocate the following test. Five cc. of a first 

 morning (overnight) sample of urine is carefully injected subcutaneously into 

 the dorsal or lateral lymph sacs of a male frog. Two or more frogs are used. 

 Each frog is then placed in a clean, dry, glass jar with perforated lid. After 

 2 to 4 hours at ordinary room temperature, any urine that is voided by the 

 frogs is examined microscopically. If urine is not present, the frog is seized 

 by the hand while still in the jar. This treatment usually results in urination. 

 Sperm in the urine denotes a positive test. 



F. The Developing Circulatory System in Relation to Nutrition, etc. 



All of the developing systems undergo gradual alterations which are inte- 

 grated with, and contribute to, the ever-changing demands involved in the 

 welfare of the embryo. However, the circulatory system is the one system 

 which must assume the burden of transport of food materials, oxygen, and 

 water to the developing systems. Synchronously it transports deleterious sub- 

 stances to the areas of elimination. While assuming this burden it also must 

 evolve its own development to bring about the structure of the adult form of 

 the circulatory system. 



A striking example of the dual burden carried by the developing circulatory 

 system is presented in the changes which go on a short time before and after 

 birth (mammals) or hatching (reptiles and birds). The placental area in mam- 

 mals and the chorio-allantoic structures in reptiles and birds act as respiratory 



