326 GEORGE W. BARTELMEZ. 



ovarian ovum as has been said. The echoes of this opinion did 

 not die out until quite recently; witness the belief that the inner 

 shell membrane is identical with the theca folliculi interna of 

 the oocyte, an idea advanced by Pander (1818), Meckel v. 

 Hemsbach (1851), Mayer (1865), Nathusius (1885) and others. 

 Needless to say none of these workers had any accurate knowledge 

 of the oviducal egg of any bird. The theory was however not 

 conclusively refuted until 1884 when Tarchanoff succeeded in 

 inserting an amber bead into the oviduct of a laying hen and 

 twenty-four hours later found it surrounded by albumen, shell 

 membrane and shell (cf. Curtis, 1914). 



Aldrovanus considered the chalazae to be the sperm of the 

 cock and Fabricius ab Aquapedente (1625) had a similar idea 

 for he supposed that they were added at the time of fertilization. 

 He considered one of them as the first rudiment of the embryo 

 and drew excellent figures of chalazae which have a ludicrous 

 resemblance to chick embryos of the fourth day. Wolff in 1764 

 confesses to having made the same error in his own juvenile 

 studies of the hen's egg. Harvey was the first to give a correct 

 account of the nature and functions of the chalazae. However 

 he says that the chalaza at the blunt end of the egg is greater 

 and longer than the other, differing in this from all subsequent 

 observers. 



A word should be said at this point concerning the various 

 layers of albumen found in the bird's egg. Immediately sur- 

 rounding the yolk and intimately fused with the vitelline mem- 

 brane is the chalaziferous albumen which is continuous with the 

 chalazee. Around this is a layer of fluid albumen which makes 

 possible the independent rotation of the yolk. Next follows the 

 dense albumen which at laying is attached to the shell membrane 

 at either end of the shell (ligamentum albuminis) so that the 

 chalazae are surrounded by the dense albumen. The space 

 between this layer and the shell membrane is filled for the most 

 part by a very fluid albumen which runs out as soon as the shell 

 is opened. The inner thin albumen is difficult to identify in the 

 laid egg of the hen (cf. Curtis and Pearl, 1912, p. 102) but Doctor 

 Blount tells that this albumen is very obvious in the "uterine" 

 egg of the pigeon. This is obviously an egg in which the origin 

 of the chalazae can be most readily studied. 



