Many cases are known of the inheritance of mutilations or malformations arising congenitally from some abrupt variation in the reproductive elements. In such cases as the one-eared rabbits, the two-legged pigs, the three-legged dogs, the one-horned stags, hornless bulls, earless rabbits, lop-eared rabbits, tailless dogs, &c., if the father or the mother or the embryo had suffered from some accident or disease which might plausibly have been assigned as the cause of the original malformation, these transmitted defects would readily be cited as instances of the inheritance of an accidentally-produced modification. The inheritance of exostoses on horses' legs may be the inheritance of a constitutional tendency rather than of the effect of the parents' hard travelling. Horses congenitally liable to such formations would transmit the liability,[66] and this might readily be mistaken for inheritance of the results of the liability. An apparent increase in this liability might arise from greater attention being now paid to it, or from increased use of harder roads; or a real increase might be due to panmixia and some obscure forms of correlation. QUASI-INHERITANCE. Of course artificially-caused ill-health or weakness in parents will tend in a general way to injure the offspring. But deterioration thus caused is only a form of quasi-inheritance, as I should prefer to call it. Semi-starvation in a new-born babe is _not_ truly inherited from its half-starved mother, but is the direct result of insufficient nourishment. The general welfare of germs--as of parasites--is necessarily bound up with that of the organism which feeds and shelters them, but this is not heredity, and is quite irrelevant to the question whether particular modifications are transmitted or not. Another form of quasi-inheritance is seen in the communication of certain infections to offspring. Not being transmitted by the action of the organism so much as in defiance of it, such diseases are not truly hereditary, though for convenience' sake they are usually so described. A perversion or prevention of true inheritance is also seen in the action of alcohol, or excessive overwork, or any other cause which by originating morbid conditions in individuals may also injure the reproductive elements.