SECTION XVII 



Malformations 



Malformations among birds are occasionally 

 observed. A complete discnssion of the dozens 

 of various forms of malformations that mav be 

 found cannot be given here for lack of space, but 

 a few facts will be given. 



In higher animal life, including man, malforma- 

 tions have been attributed to the following causes : 



External mechanical influences, such as falls, 

 blows, or severe shock of any kind, by affecting 

 the general health of the pregnant female, may 

 have power to arrest, retard, or otherwise dis- 

 turb the normal development of the embryo or 

 fetus. 



If the above should hold true in the human or 

 even animals, obviouslv it cannot do so for birds. 



The so-called spontaneous amputation, in utero, 

 by a coil of the umbilical cord finding its way 

 around a part of the fetus and causing pressure 

 and amputation, cannot hold with chickens nor 

 will acute and chronic placentitis, causing adhe- 

 sions, hardly hold for birds. 



The percentage of malformations in the human 

 family is one to three or four thousand births ; 

 in the lower animals and birds the percentage is 

 much smaller. 



During the formation of the fetus an arrest of 

 development of the bud which forms the wing 

 may result in a malformed wing ; the same can be 

 said of any other part, as the leg, beak, etc. 



If the arrangement of the groups of cells 



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