Diphyodontia Occurs. When the Struggle for Existence and Moral Hygiene
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on that method for more than six months trying to get some of stress under the influence of maternal environment results and I used the most results, with entirely negative or of factors. The therefore, must careful methods. It shows how difficult it is to these hereditary fetus, get at be prepared to pass through not only intra-uterine things. periods of stress, whose dental mark has already been indicated, but post-uterine periods as well. PERIODS OF STRESS AND THEIR DENTAL The child has not attained its full development at MARKS. the time of birth. It has within it certain potentialities, JAMES G. KIERNAN, M.D. some of which are never fully realized. There is a con- Fellow of the Chicago Academy of Medicine; Foreign Associate stant struggle between the central nervous system and Member French Medico-Psychological Association. certain bodily functions for preservation of the indi- CHICAGO. vidual and for preservation of the race, through which Despite embryologic teachings, that old notion that the central nervous system fails to reach the height man is an entity who undergoes development alone, still indicated in the child. This struggle for existence after controls pathology and physiology. The human being, birth is keenest at certain periods. Each period is however, is a animal in whom have marked by dental phenomena. The first is the period compound organs the their own nervous system and their own life under con- of first dentition. Here, coincident with-teething, is its trol of the cerebrospinal system. The child is not an the child gaining impressions of the outside world. undeveloped man, but man is an imperfectly developed is learning to walk and talk, and is also developing its child. The embryo has to contend with retrogressive eliminative organs, especially the rectum. These varied as well as factors, and the same is true of functions constitute a strain on the system, effects of progressive which most man after birth. Vertebrate embryos are of common are often evinced through the teeth and The to are an type at their origin and assume successively many com- jaws. conditions charged teething expres- mon forms before The sion of constitutional strain finding its outlet through definitely differentiating. higher the vertebrates contain in essence the organs and possibil- point of least resistance. During this first dentition, ities of all lower vertebrates. The human organism is the strain of development forces attention to the teeth, therefore a balance. While the balance is maintained and thereby leads to neglect of other factors. The teeth the organs work in unity, though there is a constant at this period should be regarded as a meter of consti- struggle for existence between them. tutional strain, and not a cause of it. Within the next During embry- 2 onic existence this struggle is more intense and diversi- period, between and 6, occurs the first great check to fied than after maturity, because of the influence of continued development of the brain. Man has learned three contending forces: remote atavism or throw-back to use his brain despite this check, but had it not he a brain to primitive types, immediate atavism or throw-back to occurred would have had higher type of to less remote ancestors of the same type, and im- use. Sometimes during this period the brain gains in finally in mediate heredity. Remote atavism tends to preserve size, albeit not balance, at the expense of the general In no structures which occur in the normal embryo only to system. small degree the struggle for existence disappear. The human heart passes through all verte- during this period of stress centers around the develop- brate heart phases. This is likewise true of the teetb ment and eruption of the 6th year molar. With the During the life of the embryo the tooth system wavers-- eruption of this molar, premature puberty, sexual pre- at one time between the polyphyodont and the diphyo- cocity, epilepsy, insanity, gout, rheumatism, obesity, dont. At this period, should the diphyodont tendency and other nutritive degeneracies, may occur. All have of man be arrested, the polyphyodont takes its place and been charged to the eruption of the 6th year molar, the human being sheds teeth as do reptiles. On the whereas its irregular or difficult eruption is, like them, other hand, should immediate atavism gain the ascend- an expression of constitutional stress. Hygiene of the ancy over remote atavism shown in polyphyodontia, teeth at this period means also constitutional, mental diphyodontia occurs. When the struggle for existence and moral hygiene. Epilepsy, for example, is not a between the two is keenest a period of stress results, disease, but a symptom of weakness of certain vasomotor which affects the organism as a whole. This stress inhibitions. The first convulsion does not constitute expresses itself most strongly in dental and maxillary epilepsy. Through a law of the nervous system, nerve action once irregularities, since the jaws and teeth are among the roused tends to repeat itself. In this way most variable structures in evolution. Under what is are established normal and abnormal habits, of which known as the law of economy of growth is governed last epilepsy is one. In its early stages a habit normal the relation of the organs to each other, and the process or abnormal is easily checked. The first convulsion, whereby one structure is sacrificed for the development therefore, could be prevented were its premonitions known. A recurrence could also were of another or for the development of the organism as be prevented the a whole. Since certain parts in the evolution of organs constitutional origin recognized. Observation of the gen- disappear and in the evolution of organisms certain eral constitution at this time, because of irregular .erup- organs through suppressive economy and since the dis- tion of the 6th year molar, would enable the physician appearing and developing tendency of necessity centers to nip epilepsy, and many other allied conditions, in around the time when certain functions are to be lost the bud. Reflex notions, however, must be flung over- by the disappearing and others gained by the developing, board. All irritations should be removed and any con- periods of stress occur around which the law of economy stitutional irregularity treated. of growth centers the struggle for existence between The obese child of 6 years, even though the obesity parts of organs and between organs themselves. It is be not excessive, should be looked upon from, a health because of this that physiologic atrophies and hyper- with There is to their standpoint suspicion. liability disease, trophies and reverse occur. Nearly all conditions and marked to weakness when under of physiologic disturbance result at these tendency systemic may periods morbid influence. These children are particularly liable Read in the Section on Stomatology, at the Fifty-second Annual to rheumatism, etc., and from Meeting of the American Medical Association, held at St. Paul, gout, profuse hemorrhage Minn., June 4-7, 1901. slight causes. Youthful obesity is sometimes associated Downloaded From: http://jama.jamanetwork.com/ by a University of Arizona Health Sciences Library User on 05/28/2015 with precocious maturity and resultant early senescence. narcotics. The struggle for existence between the de- More often it co-exists with extended infantilism, as in veloping alimentary and other systems between the the case of Dickens' "fat boy." 2d and 6th year had produced effects which are most E. S. Talbot, examining 267 corpulent school children felt during the 6th to 12th year. Provided this struggle- and adolescents, found marked of is between normal limits, the average child does not stigmata degeneracy. incur it. Ninety-two per cent, had deformed ears to a marked permanent danger from If, however, from' defect or degree. Sixty-six per cent, had arrested development, heredity, congenital improper environment,, as with their age, while 12 cent, development of the system does not proceed equably, compared per presented then strain which this excessive development. Thirty-four were too young to results, produces, during period, determine the form and size of the jaw. In 33.5 per not only the conditions already described, but the fol- cent, of the thirty-four the molars, incisors, cuspids lowing as well: and bicuspids were present. Ninety-six per cent, of NEUBOSES. PSYCHIC TYPES. these had small teeth. Eighty-seven per cent, (of the Convulsions. Hallucinations 233) had arrested development of the upper jaw; 22 Nervous laughs Anomalies of character cent, arrest of lower per cent, had Nervous coughs Aberrant sentiments per jaw. Sixty-four Love or or their Hiccoughs V-shaped saddle-shaped arches, modification, Renal and protruding teeth. Seventeen per cent, had hyper- Jealous)' of the alveolar cent, Hepatic Anger trophy process. Eighty-three per Gastric Obsessions or imperative con- had small teeth. Twenty-seven per cent, had extra Vesical cepts tubercles upon the molars. Eighty-two per cent, had Genital Pur« stenosis of the nasal cavity more or less marked. Thirty- Pulmonary Attended by impulsive acts six per cent, had deflection of the nasal septum to the Adenopathic Arson left and 29 per cent, to the per cent, Cardiac Suicide right. Twenty-one Metabolic wore-glasses for eye defect. In 58 per cent, there was Homicide of the and in 7 cent, Stuttering Alcoholism enlargement thyroid gland, per '•Tier," Theft arrest of development of it. In 296 cases of early lipo- matosis male and 116 under Neuralgias Rape (180 females) coming my Neurasthenia Non-criminal acts own there were 10 6 observation, cryptorchids, hypo- Ecstasy Night terrors spadiacs and 3 cases of pseudo-hermaphroditism. Three Hysteria Idiocy females had infantile bifid uteri.