CLASSIFICATION OF THE DISEASES OF NUTRITION The foregoing discussion on etiology and pathogenesis has demon strated that our points of view are in a transition stage, and have attained no definite clearness. A survey of the attempts at classifica tion of the diseases of nutrition by various authors offers a still more unpleasant perspec ti VC .
The older attempts at classification, although they lacked a patho logic, bacteiial, and chemical foundation, and were based entirely upon the rather vague symptomatology of these diseases, nevertheless suc ceeded, through the masterly power of observation of the investiga tors, in defining particular types, which we must recognize even to-day on account of their defi»ite clinical characteristics, and which must form the basis of any classification based upon our broader knowledge of pathogenesis. Passing over these older labors, we must next consider von Widerhofer's classification, which is based upon the anatomical findings. Although this author in his discussion of diseases of the stomach (of which lie describes no less than 15 different types), sticks pretty closely to post-niorton findings, yet in gastro-enteric diseases lie has to fall back partly upon the clinical course, and speaks, among other things, of dyspepsia, cholera infantum, and so forth. Anatomic research has thrown valuable light on the subject of infantile patho logic anatomy, which I shall discuss thoroughly in the next chapter, but it can not be used as a basis for classification of this group of dis eases, because the anatomic types corresponding to the particular forms of disease are not sharply enough outlined. Another point against such a classification is the fact that frequently the severest clinical symptoms give negative, or almost negative, post-mortem limlings.
For this reason Baginsky, who among modern writers places the highest value upon the anatomical findings in gastro-enteric affections, has been compelled to forsake this basis in his attempted classification. He, like so many others, has not remained true to his original scheme, so that with respect to this matter inconsistency- is the rule, Thus to Escherich we owe three distinct systems of classification, differing not only in the number of forms described, but also in essential principles; Lesage advances a new proposal in almost every publication; and we find in the various French monographs wholly diverging classifications which are based at times upon bacterial etiology, and at other times upon clinical standpoints (Alarfan, Rothschild, Nohecourt, Ardoin, etc.). Actual progress was made when Heubner first sharply differentiated the various forms according to the. methods of feeding the infant, which differentiation is accepted by Czerny and Keller in their text book.
Since our knowledge of the nature of the various diseases of this class is still in process of development, it is for the present impossible to take etiologic standpoints. as the basis of a principle of classifica
tion, even when mixed with clinical facts. The idea of "digestive infection," as conceived, for example, by Lesage, Thiercelin, and others, has a significance only for that class of eases in which we can demon strate with certainty- the action of organic exciting agents. But there are a number of processes, in which parasites of endogenous or exogenous origin play either no part, or a very unimportant one. Nevertheless such processes must also be given a place in a scheme of classification. We must require of our scheme that it will enable us to diagnose correctly through our clinical methods ever.- disease met with clin ically, except rare and exceptional cases, and to place it under its proper heading. Further difficulties are encountered in the multiple interrelation of the processes, by which a gastro-enteric affection of acute onset may end in a chronic stage, or Nice versa prolonged disturb ances of digestion may undergo acute exacerbation. Also, as often occurs in such combinations, the imperceptible transition of individual types into one another, and the successive involvement of the various divis ions of the alimentary canal, are further sources of confusion. From all these circumstances the boundary lines must remain movable, and yet find their expre.ssion in the classification scheme. Taking these considerations into account, Czerny and Keller have divided the cliseases into three great groups, which they designate: (I) disturbances from alimentation ; (2) disturbances from infection ; (3) disturbances frotn congenital defect. in the constitution and body structure. They- add the proviso that a child can at one time manifest disturbances which belong in several of these groups. But their further attempt to sub divide the disturbances from alimentation into milk-injuries, starch injuries, proteid-injuries, and gluten-injuries, seems to be too schematic, because the individual components of the food do not manifest their injurious action with a clearness sufficient for the construction of a definite clinical picture. Also the efficacy of a special feeding therapy, based on diagnosis, in allaying the corresponding Msturbances irdist not be given too one sided a significance, since other factors such as re striction in the amount of food, proper fee(Eng intervals, and general hygiene of the child are operative in producing the result. Moreover, too sharp a di VIS1011 of cow's milk injuries acconling to their bacterial and chemical nature cannot easily be applied in practice. On account of the great individual differences in the reaction of different children, w-e can never be sure what bacterial content in milk can be borne by the child without result, and consequently cannot tell whether the disturbances present are to be attributed to bacteria, or to insufficient absorption of the fat, carbohydrate, and so forth.