assimilating synthesis] ate simultaneously produced in every living being, in a connection which cannot be broken. The disorganization or dissimilation uses up living matter [by this we must understand the reserve-stuff, as will be seen later on in the quotation] in the organs in function: the assimilating synthesis regenerates the tissues; it gathers together the reserve-stuff which the vital activity must expend. These two operations of destruction and renovation, inverse the one to the other, are absolutely connected and inseparable, in this sense at any rate, that destruction is the necessary condition of renovation. The phenomena of functional destruction are themselves the precursors and the instigators of material regeneration, of the formative process which is silently going on in the intimacy of the tissues. The losses are repaired as they take place; and equilibrium being re-established as soon as it tends to be broken, the body is maintained in its composition."
It is perfectly right and wise to say with Claude Bernard that the two orders of facts are successive, and that one is normally the inciting condition of the other. The possibility of the development of the yeast when fermentation fails, and the weakness of this development on the other hand under these conditions, are an excellent proof of this. The one proves the essential independence of the two orders of facts, the other the inciting and provoking virtue of the first relatively to the second. The experimental truth is thus expressed with a minimum of uncertainty. We know the facts which led Le Dantec to formulate his law of functional assimilation—namely, that the functional activity is useful or indispensable to the growth of the organ; that the organs which are
