Supra dictum est, habitus est quaedam dispositio alicuius subiecti existentis in potentia vel ad formam, vel ad operationem. Secundum ergo quod habitus importat dispositionem ad operationem, nullus habitus est principaliter in corpore sicut in subiecto. Omnis enim operatio corporis est aut a naturali qualitate corporis, aut est ab anima movente corpus.
As we have said above (q49 a2 seqq.), habit is a certain disposition of a subject existing in a state of potentiality either to form or to operation. Therefore insofar as habit implies disposition to operation, no habit is principally in the body as its subject. For every operation of the body proceeds either from a natural quality of the body, or from the soul moving the body.
Quantum igitur ad illas operationes quae sunt a natura, non disponitur corpus per aliquem habitum, quia virtutes naturales sunt determinatae ad unum; dictum est autem quod habitualis dispositio requiritur ubi subiectum est in potentia ad multa.
Consequently, as to those operations which proceed from its nature, the body is not disposed by a habit, because the natural forces are determined to one mode of operation; and we have already said (q49 a4) that it is when the subject is in potentiality to many things that a habitual disposition is required.
Operationes vero quae sunt ab anima per corpus, principaliter quidem sunt ipsius animae, secundario vero ipsius corporis. Habitus autem proportionantur operationibus, unde ex similibus actibus, similes habitus causantur, ut dicitur in II Ethic. Et ideo dispositiones ad tales operationes principaliter sunt in anima. In corpore vero possunt esse secundario: inquantum scilicet corpus disponitur et habilitatur ad prompte deserviendum operationibus animae.
As to the operations which proceed from the soul through the body, they belong principally to the soul, and secondarily to the body. Now habits are in proportion to their operations: whence "by like acts, like habits are formed" (Ethic. ii, 1,2). And therefore the dispositions to such operations are principally in the soul. But they can be secondarily in the body: to wit, insofar as the body is disposed and enabled with promptitude to help in the operations of the soul.
Si vero loquamur de dispositione subiecti ad formam, sic habitualis dispositio potest esse in corpore, quod comparatur ad animam sicut subiectum ad formam. Et hoc modo sanitas et pulchritudo, et huiusmodi, habituales dispositiones dicuntur. Non tamen perfecte habent rationem habituum, quia causae eorum ex sua natura de facili transmutabiles sunt.
If, however, we speak of the disposition of the subject to form, thus a habitual disposition can be in the body, which is related to the soul as a subject is to its form. And in this way health and beauty and such like are called habitual dispositions. Yet they have not the formal aspect of habit perfectly, because their causes, of their very nature, are easily changeable.
Philosophus, in praedicamentis, sanitatem corporis, vel infirmitatem insanabilem, habitum nominari dicit.
The Philosopher says in the Book of Categories (De Categor. vi) that health of the body and incurable disease are called habits.