In Fig. 67 are seen the teeth of an individual affected with constitutional disease (referring to Fig. 51 it becomes evident that the defective lines represent the respective ages, 2-1/2, 4, and 5 years). The degree of pitting will depend, as a rule, on the severity of the constitutional disorder. In the case just cited, however, although nutrition was but slightly disordered, each tooth shows a tendency to conate. Not infrequently cavities extend completely through the tooth. The cusps of the (permanent) first molars, calcifying at the first year, are usually attacked also, and arrested in development, producing the cone shape. These data, together with the dates of eruption of the temporary and permanent teeth, furnish an absolute basis for calculation as to malnutrition producing excessive or arrested development, not only of the teeth and jaws but all parts of the body. [Illustration: FIG. 68.] [Illustration: FIG. 69.] [Illustration: FIGS. 70, 71.] Fig. 68 shows a very degenerate jaw with cone-shaped, malformed bicuspids. The right lateral missing, the cuspids are erupting in the vault and the dental arch is assuming a V-shape. The jaw shows, as a whole, marked arrest in development. Fig. 69 shows Hutchinson's teeth. Were the first molars visible, they would present marked contraction of the outer surface with a malformed centre. Referring again to Fig. 51, it is observable that trophic changes affected the system at the age of birth. The outer surface exhibits a tendency to take the cone shape. Figs. 70, 71, 72, 73, and the molars in Fig. 66, exhibit malformations that assume the cone shape and the centre frequently associated with this type of teeth. The coincidence in form between Hutchinson's and malformed teeth and those of the chameleon suggests that tropho-neurotic change produces atavistic teeth. Fig. 74 illustrates the tendency of human bicuspids (when there is no antagonism) to rotate one-fourth round, thus again indicating an atavistic tendency toward the teeth of the chameleon. Fig. 75 exhibits extreme atavism; all teeth anterior to the molars are cone-shaped. The third molars are missing and would, probably, never erupt. In Fig. 76 appears more marked atavism. The upper and lower are both cone-shaped, and the superior first bicuspid exhibits tendency thereto. The right superior second bicuspid, second and third molars, the right inferior first and second bicuspids, with second and third molars are missing. The same condition, probably, exists on the left side. The space in the upper jaw is due to the insufficient width of the teeth. Alternation of teeth in the upper and lower jaw is a reptilian feature. [Illustration: FIG. 72.] [Illustration: FIG. 73.] [Illustration: FIG. 74.] [Illustration: FIG. 75.]