26 PRINCIPLES OF STOCK-BREEDING. 



other scrofulous affection, while the tendency to lung- 

 disease may make its appearance in the next or some 

 subsequent generation. 



The same may be said of all so-called " constitu- 

 tional diseases," the organ affected determining the 

 character of the symptoms that indicate the presence 

 of the general defect of the system. 



When the general constitutional predisposition is 

 inherited, the conditions to which the animal is sub- 

 jected as to food, exposure, etc., may have an influ- 

 ence in determining the particular organ in which the 

 disease is developed. 1 



Dr. Gross says, " The children of consumptive par- 

 ents are often cut off by the same disease, or they 

 suffer in various parts of the body, as the bones and 

 joints, lymphatic ganglions, eye, ear, and serous mem- 

 branes." a 



In 1,000 cases of consumption tabulated by Dr. 

 Cotton, 367 were hereditary, and of these the brothers 

 or sisters were likewise affected in 126 cases. Of the 

 114 males whose parents were affected, 59 inherited 

 the disease from the father, 40 from the mother, and 

 15 from both. Of the 127 females whose parents 



1 The injudicious use of active medicines may also be mentioned as 

 an efficient exciting cause of the development of a disease to which the 

 animal is predisposed, and the organs subjected to the action of such 

 medicines will in all probability become the seat of the affection. A 

 severe cathartic, for example, may thus develop the hereditary tendency 

 to chronic diarrhoea or dysentery ; or a profuse bloodletting may lower 

 the general tone of the system, and thus favor the influence of other 

 depressing agencies in developing the disease. 



8 "System of Surgery," vol. i., p. 265. Sec also Dr. Allen on "He- 

 reditary Disease," p. 7. 



