GENERAL CONSIDERATION OF DISEASE. 37 



of his male colts were cryptorchids. About fi^o of tRe male 

 progeny of one of Missouri's most famous boars, Chief Tecum- 

 seh II, were cryptorchids. Liberty Chief and Chief I Know, 

 two boars sired by Chief Tecumseh II, were noted boars and 

 from 3 to 5% of their male get were cryptorchids. Chief Per- 

 fection II, also sired by Chief Tecumseh 11, was the sire of Che- 

 rokee Perfection which in turn sired about :>7d of cryptorchids. 

 Thus this structural defect appeared in at least three genera- 

 tions. A female Belgian hare having one ear, produced a large 

 number of young of which more than .50% had only one car. 



Epileptic domestic animals and those affected \\ith other 

 nervous disorders are usually destroyed or at least are not bred, 

 hence the statistics of inherited nervous diseases in dimiestic 

 animals are very meagre, but there is little doubt that such 

 diseases, or at least a predisposition to them, is inherited. La 

 Notte recorded hercditarv ei>ilepsv in the progeny' of two epi- 

 leptic bulls, the disease becoming evident in the females after 

 thev had given birth to their first calves, and in bulls soon after 

 thev were put into service. 



Some other diseases are inherited, thus ; periodic ophthalmia 

 has, in man\' instances, occurred in, and affected practically an 

 entire family of horses. There is a firedisposition to spavins, 

 splints and ringbones in certain strains of horses. This is due 

 to inheritance of structural or conformation defects. 



ACQUIRED DISEASES. 

 The life of mammals is conventionally divided into two 

 periods, the ante-natal or intrauterme. and the post-natal or 

 e.xtrauterine. .\cquired diseases are those contracted after 

 fertilization and hence may he ante-natal, (congenital) or post- 

 natal. 



Jntc-iiatal or Congenital diseases are those contracted be- 

 tween the time of fertilization and birth. Some infectious diseases 

 are congenital, for instance, marked lesions of tuberculosis were 

 found by the writer in 1900 in a three day old calf, and two 

 authentic reports of similar cases have been received since that 

 date. (These cases were not considered as inherited for the 

 reason heretofore given, and in all three cases lesions of tuljercu- 

 losis were found in the uterus and adjacent tissues of the cows.) 

 Infectious disease^ are seldom transmitted from the mother to 

 the foetus because of the relation and anatomical structure of the 

 placental membranes. The female is usually either sterile or 

 aborts if the uterus or the accessory parts are diseased, while 

 the male is not likely to be productive if the genital organs are 

 diseased. Exanthematous diseases are frequently congenital. 



