CONGENITAL AND INHERITED DISEASES 



If there exist at time of birth in an individual actual disease, 

 or peculiarities of predisposition or immunity which also char- 

 acterized the parents or ancestors, such conditions are said to be 

 congenital (innate), and in the latter instance inherited (heredi- 

 tary) as well. The genesis of such an occurrence is by no means 

 always the same, although in a measure it is apparently dependent 

 upon conditions of the parents. 



During intrauterine life the embryo may experience injuries 

 affecting its normal growth, causing deformity, interfering with 

 the proper development of a limb or organ, or destroying some 

 part already in stage of development. Such injuries are for the 

 most part mechanical in type, as where amniotic adhesions (or 

 more rarely tumors of the uterus) by constriction or pressure of 

 this or that part of the foetus (which in its movements might be 

 entangled in the amnion) may compress, wound or otherwise 

 injure it. Depending on the nature of such an injury, the embryo 

 may in consequence present gross or trivial faults of one sort or 

 another; these are spoken of as foetal or emhryogenous anomalies, 

 Z'itia congenita, developmental defects or monstrosities. Except 

 when a uterine lesion is the cause of the deformation of the foetus, 

 the mother has no influence upon the production of anomalies in 

 the offspring. 



There are a number of infectious diseases whose causative 

 micro-organisms are capable of gaining access to the foetus indi- 

 rectly through the placenta. In .their multiplication in the pla- 

 cental tissue they may, by growth, penetrate it and obtain entrance 

 to the blood of , the foetal side. Under such circumstances the 

 newly born animal carries into the world with it the same disease 

 from which the maternal parent was sufferinig during the term of 

 her pregnancy; the acquirement is here placental. The most com- 

 mon example , of such a transmission is seen in congenital tuber- 

 culosis in cattle, occurring only in case the cow has uterine tuber- 

 'culosis. The congenital pathological conditions of this type have 



