Since the application of cooking to food there has been a progressive lessening in the work of the jaws and teeth and, parallel with this, a diminution in their size and an incursion of dental caries. Among the anthropoids in their natural state caries is practically unknown, and I think we may conclude that the same was true of man before he learnt to cook. In the pre-agricultural races, such as the aboriginal Australians, the effect of cooking the food is shown in the lessening in the size of the wisdom teeth and of the post-wisdom alveolar ridge; dental caries, though rare among these people, does occur, and especially in the wisdom teeth.[27] In the early agricultural period, owing to the increasing softness of the vegetable food, the jaws and teeth show a tendency to be smaller than in the previous periods; the wisdom teeth are decidedly smaller and more prone to caries, while caries of the other teeth is by no means rare. In the late agricultural period the jaws and teeth often show very decided defects of development, while dental caries is, as we know but too well, rampant. What has been said concerning the relative prevalence of caries in different diet epochs applies to many other diseases of the teeth; thus, along with the increase of caries, there has been a parallel increase in the prevalence of pyorrhœa alveolaris. CONCLUDING REMARKS I have now set forth some of the evils resulting from inefficient mastication. They are many and serious. The immediate evils, such as over-eating, indigestion, adenoids, dental caries, and pyorrhœa alveolaris, are bad enough, but when we consider the secondary evils to which these primary ones give rise,--and I have only mentioned a few of them,--we must come to the conclusion that an appalling amount of misery and suffering may be saved by the simple expedient of inculcating the habit of efficient mastication. How this end can best be accomplished will be considered in the next section. SECTION IV. From _London Lancet_, August 8, 1903 MEANS OF INSURING ADEQUATE MASTICATION