102 RAYMOND PEARL AND MAYNIE R. CURTIS 
THE DISTRIBUTION OF THE DIFFERENT KINDS OF ALBUMEN IN 
THE EGG 
In the normal egg of the hen there are certainly three and 
possibly four different albumen layers which can easily be dis- 
tinguished on the basis of physical consistency. These are: 
(A) the chalaziferous layer. This is a thin layer of very dense 
albuminous material which les immediately outside the true 
yolk membrane. It is continuous at the poles of the yolk with 
the chalazae, and is undoubtedly found in connection with those 
structures. It is so thin a layer that it might well be, and often 
has been, taken for the yolk membrane. (B) The inner layer 
of fluid (thin) albumen. This layer is only a few millimeters in 
thickness and there is some doubt as to its existence as a sep- 
arate, distinct layer. (C) The dense albumen. This is the layer 
which makes up the bulk of the ‘white’ of the egg. It is com- 
posed of a mass of dense, closely interlaced albumen fibres, with 
some thin fluid albumen between the meshes of the fibrous net- 
work. The dense albumen as a whole will not flow readily, but 
holds itself together in a flattened mass if poured out upon a 
plate. (D) The outer layer of fluid albumen. ‘This is the prin- 
ciple layer of thin albumen, which makes up the fluid part of 
the ‘white’ observed when an egg is broken. 
Three of these layers, A, C, and D are readily demonstrable 
and there can be no question whatever as to their existence. 
Regarding the existence of B as a separate and distinct layer 
there is more doubt. Gadow? definitely asserts the existence of 
such a layer in the following words: ‘‘Dicht auf der Dotterhaut 
befindet sich eine diinne Lage des fliissigen Eiweisses.” It is 
possible that what has been taken by previous observers to form 
this layer B is only a little thin albumen squeezed out of the 
meshes of the dense layer (C) when the egg is broken. 
Let us now consider the distribution of the different sorts of 
albumen in eggs at different stages in their passage down the 
oviduct. The following extracts from autopsy protocols are to 
the point here. 
* Gadow, H., Vogel (Anatomischer Theil); in Bronn’s Klassen und Ordnungen 
des Thier-Reichs. Leipzig, 1891, p. 869. 
