Quantitative laws in biological chemistry

INTRODUCTIONwere introduced.Chemistry at that time con- sisted of a large number of descriptions of known substances and their use in the daily life, their occurrence and their preparation in accordance with the most reliable receipts, given by the foremost masters of the hermetic (i.e.occult) art.In the same manner Biochemistry up to a quite recent time consisted of a great number of descrip- tions of different products accompanying living organisms, their properties, use, and their composi- tion, i.e. their content of hydrogen, oxygen, nitrogen, sulphur, phosphorus or perhaps other elementary substances.If possible this composition was expressed by means of a chemical formula.But even the quantitative element which is con- tained in an analysis of the composition of a sub- stance was lacking in cases where the substances investigated occur in such small proportions that it is not possible to isolate them in a pure form.We have no other possibility of describing these substances than by indication of their occurrence and mode of preparation in the most concentrated and purest possible form, with an indication of their character- istic properties, unless we employ methods other than those belonging to the old classical science of Chemistry.Only by the use of the methods introduced toy the modern physical chemistry is it possible to form an opinion of the manner in which these substances react, and thereby to get a clear scientific idea of their nature.The fundamental fact must here be recalled that these substances If now a variable quantity y is dependent upon another quantity x> which we may change as we wish, for instance temperature or concentration, so that the formula expressing this dependency possesses the form where a and b are two experimentally determined constant values, then the graphical interpretation only if we measure special points on it, and determine cor- responding values of z and /, do we get a real representation of the meaning of the curve.In this case a table giving the comparison of calculated Then glands in the walls of the stomach secrete the stomachical juice, which contains two active substances, \he pepsin, which decomposes the albuminous substances of the food into invertase, which decomposes cane -sugar ; and maltase, which splits up maltose.In general, micro-organisms produce a large number of substances of high chemical activity.Amongst these a great many are of the highest interest for us, as, for instance, the diphtheria toxin or the tetanus-poison, which cause the terrible diseases diphtheria and lock-jaw.Even higher organisms, as snakes or spiders or insects, produce similar poisons, as do also some plants, e.g.Abrus praeca