Again, these changes of the atmosphere, which produce these effects on the sane, seem, on the insane, in many cases, to be wholly expended in producing fluctuations on the animal spirits (not in bodily effects,) so expended, as if this increase of the vital energies were neither subject to the usual laws of corporeal nor intellectual distribution. These insane, consequently, are less subject to disease from these causes, as if they, no longer responsible, paid not, therefore, the price of the use and abuse of the energies continually imparted to all. It is true, that the life they lead, not only removes them from many causes of disease, but the very nature of their diseased state, also, renders the mind more susceptible of impressions, for, beside their excited state, by being shut out from the world, they necessarily give to trifles all the importance of weightier matters, and thus it is, that by their being the victims of mental excitement, {133a} which is every where a protection against prevailing diseases, they are not so liable to be attacked by the prevailing epidemics. {133b} Whatever influences prevail externally, they must in all cases, sane and insane, be counteracted and modified by internal influences. But to enter upon this investigation is not at present my intention, therefore I shall not now examine the question, whether the epidemics of different times, and the character of all diseases, which always partake, more or less, of the prevailing epidemic, can be _wholly_ {134} explained as being caused by some difference in the prevailing state of the weather. I shall only remark that it is certain such seasons and states of the weather are equally fruitful in the production of insanity and in the excitement of those already insane. Yet, from these internal mental or moral influences, it is evident that neither insanity nor epidemic diseases can prevail exactly in proportion to the state of the weather, unless it could be proved there always existed a correspondence between the state of the weather and the moral and physical susceptibilities or predisposition of the persons exposed to its influence. At the same time I assert that our moral state has more to do with disease, either directly or indirectly, than is generally credited, yet these moral causes are necessarily every where physical in their operation, so that the assertion that our physical corresponds with our moral state, and what we call physical causes are the effects of this state, need not alarm us, in fact, the interesting truth is now demonstrated, {135} that health and longevity correspond with our moral state, (though this is true as a general principle, there are many real and apparent exceptions,) in fact, natural and moral effects co-operate, just as the circulation depends on the nervous energy, so the nervous energy depends greatly on our mental condition.