Molina, treating of mutilation, says[6] it does not exist unless there is an amputation or shortening (_detruncatio_) of a member. When a foot or hand is so weakened without amputation that it cannot exercise its function the person is said to be maimed or lame, not mutilated. He holds that a finger, and _a fortiori_ a phalanx of a finger, are not properly members. In defining mutilation as a cause of canonical irregularity[7] he contends that the weakening of a member so that it cannot perform its function is not a true mutilation canonically. He does not agree[8] with Cajetan, de Soto, and others who hold that an important part of a whole member is equivalent to a member so far as technical canonical mutilation is concerned. Molina says that a part of the body as a member to fulfil the requirements of the law on mutilation as a cause of irregularity must have a distinct, complete function of its own, not be a mere part conducing to the function. Ballerini[9] agrees with Molina, but he draws attention to a decretal of Innocent I. which makes an amputation by oneself of even a part of one's own finger a full canonical irregularity, because of the unnatural quality of the act.
[6] _De Justitia et Jure_, disp. 19, tr. 3.
Suarez defines mutilation thus: "Mutilare significat proprie membrum aliquod abscindere"[10]--to mutilate means, strictly speaking, to cut off any member. He holds with Cajetan that an important part of a member is in itself equivalent to a member. A reason he offers for his opinion is that a eunuch is enumerated among those who are canonically mutilated, but the eunuch, he tells us, "does not lack any member which in itself has a function in the body independent of all other organs." This is not true. The testicles, which the eunuch lacks, have two distinct functions, independent of other organs--they make the spermatozoa and an important internal glandular secretion. These facts were not known in Suarez's time (1548-1617). Suarez adds this remark: "There can be a grave sin in a marring [_diminutio_] of any chief member, although there may be no grave mutilation; as, for example, to cut off a part of a finger is undoubtedly a mortal sin, yet, in the opinion of all moralists, it is not enough to cause irregularity."