108 R. J. ANDERSON [aveust 1899 
mechanical and due to the nature of the roosts. These breeders look 
upon the weakness naturally associated with the preparation of pure 
breeds of fowls as a predisposing cause. 
Light pure bred fowls have been often observed to have crooked 
keels, whilst heavy breeds, if the birds are not allowed to roost early, 
have not the deformity. The following is a note from a breeder :—* A 
‘black Norfolk turkey’ with a crooked breast was mated with a 
straight-breasted hen. All the chicks got the same treatment, the 
roosts were low and flat, and covered with straw until the birds were 
able to fly.” Notwithstanding these precautions five cock birds out of 
the sixteen birds which formed the flock had crooked breast keels. 
Water-fowl have sometimes crooked breasts; the deformity here is not 
due to roosting. The most crooked sternum in my possession belonged 
to a Brahma. The keel, where the bend is greatest, is nearly hori- 
zontal. There are marks of pressure on the keel edge in some cases. 
A distinct broadening of the edge of the keel is perceptible, in two bent 
to the right, and in four bent to the left. An indentation occurs in 
front of the middle of the two keels bent to the left. Two keels have 
marks of having been broken and reunited. The wry tail has been 
attributed to the bird roosting too near the wall, and to the tendency 
to form a compensating bend in consequence of the breast being bent 
to the opposite side. The fanciers who believe that it is due to in- 
herent weakness because of the breeds being run out, seek to correct 
the tendency by the introduction of new stock. The wry-tailed birds 
are discarded. The evidence goes to prove that— 
(1) Malformation is commonest in pure breeds. 
(2) In-and-in breeding tends to develop wry tails and crooked keels. 
(3) The distortion is frequently transmitted from parent to off- 
spring. 
(4) Roosting on round or sharp roosts tends to promote the 
distortion. 
Summary. 
(1) The shape of a body may be due to forces within or pressure 
without, or both. 
(2) The same kinds of symmetry are to be observed in inorganic 
and organic forms. 
(3) The forces at work inside organisms are “ vital” and physical. 
The resultant figures are the expression of the work of two 
or more sets of agents. 
(4) Asymmetry may be due to causes internal or external, or both. 
I have to thank Dr. G. J. Allman for the opportunity of con- 
sulting his father’s manuscript. 
QUEEN’s COLLEGE, 
GALWAY. 
