Sept. 18, 1916 Dwarf Eggs 103 1 



the yolk present in the normal egg found in the isthmus. Since the egg 

 record of the bird is not available, it is impossible to say whether the yolk 

 discharged from the second large follicle had been contained in a normal 

 egg laid within a day or two before death, or whether it had been absorbed 

 with great rapidity from the body cavity. It has been shown by Pearl 

 and Curtis (6, 16) that "yolks and partly or fully formed eggs may be 

 absorbed rapidly and in large numbers from the peritoneal surface." 

 Previous observations, however, would not lead us to expect that within 

 the normal period of the formation of an egg in the duct the absorption 

 of a yolk would be so complete that no trace of it could be found. It 

 seems probable that the sex organs remained in a condition capable of 

 response to a stimulus for egg production for a few hours after ovulation. 

 The presence of two large follicles, however, shows that in this case 

 also the sex organs were in the extreme of active condition. 



In case an autopsy was not performed upon a bird which produced a 

 dwarf egg the morphological condition and the physiological state of 

 the sex organs at the time the dwarf egg was laid can be judged reason- 

 ably accurately by the egg record. In all cases not discussed under the 

 section on abnormal physiological conditions associated with dwarf- 

 egg production the dwarf egg was produced within a litter all the other 

 eggs of which were normal. As already shown, the dwarf egg took any 

 position in the clutch and litter. In all cases there was abundant evi- 

 dence from the egg record that the sex organs were in active condition 

 and were capable of producing normal eggs. 



In the center of the thick albumen of every dwarf egg examined was 

 found some firmer material. In a number of cases this firmer nucleus 

 was simply a few coagulated threads of albumen which resembled the 

 threads of a normal chalaza. Sometimes the mass of threads has the 

 appearance of a normal chalaza, but more often it is an irregular mass of 

 untwisted threads. Such a mass of threads, or one, rarely two, more or 

 less perfect chalaza, is present in nearly all the dwarf eggs. Frequently 

 it is accompanied by one or more small slightly reddish lumps which 

 appear to be hardened albumen, or by small blood clots, or more fre- 

 quently still by a drop or more of yolk. It has already been stated that 

 more than half of all the dwarf eggs collected contained some yolk not 

 in a yolk membrane. In these cases the yolk is frequently surrounded 

 by a membrane-like layer of coagulated albumen fibers resembling a 

 chalazal membrane. In many cases nearly normal chalazae are attached. 

 The contents of such an egg is shown in Plate CXIII, figure 3. In most 

 of these cases there is no normal yolk membrane in the egg, but in a few 

 cases the dwarf egg contained a ruptured normal yolk membrane from 

 which most of the yolk had escaped. Beside these, each of a number of 

 dwarf eggs contained a small yolk without a germ disk but inclosed in a 

 complete vitelline membrane. 



