December 30, 1921] 



SCIENCE 



665 



tion it was observed some months ago that 

 injections of therapeutic doses of the active 

 principle of the posterior lobe of the pituitary- 

 body sometimes causes a premature expulsion 

 of the bird's egg from the oviduct. Soon 

 afterward it was easily established that a 

 somewhat larger dosage could be relied upon 

 to cause an immediate expulsion of the egg 

 from any part of the oviduct. Doubtless this 

 action might have been anticipated from the 

 well-known action of this secretion on the 

 uterine muscle of mammals. The immature 

 or oviducal egg can be utilized to much ad- 

 vantage in the investigation of several kinds 

 of biological and chemical problems but the 

 impracticability of obtaining such eggs — ex- 

 cept through the often uncertain, ever ex- 

 pensive and self-limiting process of killing 

 the mother bird — has hitherto handicapped 

 such studies. It therefore seems worth while 

 to describe this simple and useful method. 



A full understanding of the method and its 

 limitations involves the following facts con- 

 cerning the premature egg: The bird's egg 

 requires between 1 and 2 days to pass from 

 the ovary to the exterior. In pigeons this 

 pieriod of passage down the oviduct is a little 

 more than 40 hours. When the ovarian egg 

 is laid it has therefore already undergone 

 development during this number of hours and 

 has had various accessory parts (albumen, 

 shell-membranes, shell) added to it. The first 

 10 to 15 hours of this period involve the for- 

 mation of albumen, while the shell is con- 

 tinually formed during the last 25 to 30 

 hours. The middle and lower portions of 

 the oviduct are more highly muscular in 

 structure than is the extreme upper portion 

 (infundibulum, funnel) into which the egg 

 first passes from the ovary. The movements 

 which propel the egg along the oviduct are 

 involuntary in origin; in the final muscular 

 act of egg-expulsion voluntary action is also 

 involved. In the dove or pigeon the egg is 

 easily and positively palpable 30 hours before 

 the normal time of laying. 



The effectiveness of the method is suffi- 

 ciently indicated in the table which has been 



constructed from the last series of injections 

 made by us. It will be observed that, with 

 few exceptions, the eggs were laid within 6i 

 to 25 minutes following the injection. They 

 were laid at stages of immaturity varying 

 from 4 to 26 hours. Four cases required a 

 repetition of the injection. The egg sought 

 at the 37-hour stage (No. 8) was not forced 

 backward but forward into the body cavity — 

 a fact later verified by abdominal operation. 

 A 34-hour stage (No. 11) was, however, 

 forced neither forward nor backward by a 

 dosage one-half of that used in the other 

 tests. In the case of one quite wild common 

 pigeon (No. 14), injected late at night, three 

 injections failed to cause the immediate ex- 

 trusion of the egg, though they quickly forced 

 the egg down to the extreme posterior part of 

 the oviduct. The time limits involved in this 

 case are uncertain. Egg No. 6 was laid with- 

 out shell but with the membrane. Several 

 eggs had very little shell while those taken 

 only 4 to 10 hours before the normal period 

 of laying were fairly provided with shell and 

 were capable of incubation in the normal 

 manner. The injections are nearly as effec- 

 tive in the common fowl, though in this case 

 it is not possible to know the exact number of 

 hours of immaturity of the egg thus secured. 

 The injections are made hypodermically 

 (No. 1) or better intramuscularly into the 

 broad muscles of the breast. Pituitrin of 

 Parke, Davis and Co. was used in the in- 

 jections cited in the table. It is unnecessary 

 to use the preparation designed for use in 

 obstetrics (used here in Nos. 9, 10, 11, 15, 16, 

 17) since the difficulty of infecting birds 

 makes the use of pituiti'in (oral) practicable. 

 The size of the effective dose depends largely 

 upon the age of the preparation. One prep- 

 aration evidently made six months later 

 than another was found to be twice as active 

 as the older preparation. The dosage for the 

 weaker preparation, which is perhaps near 

 the average age of preparations on the mar- 

 ket, was found (it was used in data of table) 

 to be about 0.133 c.c. per kilo body weight. 

 This dosage is about 4 times that used for 



