570 



SCIENCE 



[N. S. Vol. XXX. No. 77S 



tially injurious substances in quantities not 

 injurious, since the language of the law in the 

 use of the word " may " specifically and very 

 properly provides against such additions. The 

 law reads : " If it contain any added poisonous 

 or other added deleterious ingredient which 

 may render such article injurious to health." 

 It is not whether the quantity does render the 

 food deleterious, but whether the added sub- 

 stance is possessed of a deleterious action 

 which is " the nature, the property, the quality, 

 the effect " of such added substance. If it is, 

 the substance is essentially injurious and its 

 addition to food is adulteration ; while, on the 

 contrary, if such added substance is only 

 capable of becoming deleterious in the sense 

 that food itself may, then, clearly, it is not the 

 intent and meaning of the law to regard such 

 added substance as essentially deleterious or 

 its addition to food adulteration because of 

 any such deleterious possibility. 



First, then, it is important to appreciate 

 clearly the sense in which food itself may be 

 deleterious. Considering food that is not 

 adulterated and is suitably prepared for inges- 

 tion, a normal individual may ingest in a 

 normal manner a certain quantity without 

 injurious or deleterious effect. If the quan- 

 tity is increased an amount will finally be 

 reached which is in excess of the needs of the 

 body. However, the body is capable of adapt- 

 ing itself for a time to the ingestion of some 

 excess by certain physiological adaptations, 

 such as by the storage of caloric foods, by the 

 rapid elimination of water or by the tonic 

 control of reactions to stimulating foods; but 

 when the quantity is increased beyond the 

 capacity of such adaptations the food becomes 

 injurious to health and a train of symptoms 

 referable to poisonous or deleterious action is 

 produced. This is true notwithstanding the 

 healthfulness of the food in proper amount. 

 This injurious effect is, then, not an essential 

 quality of the food in question, but a quality 

 dependent upon the ingestion of an excessive 

 quantity of the otherwise healthful food, that 

 is, a quality dependent upon the quantitative 

 relation. Every food is deleterious if the 

 quantitative relation be disregarded; it is 



healthful only within the limts of physiolog- 

 ical adaptation to the quantity ingested. 

 When these limits are exceeded it becomes in- 

 jurious. Such deleterious action, however, is 

 not an essential quality of food, since in lesser 

 amounts, as a rule widely separated from the 

 quantity capable of producing injury, the food 

 does not have such deleterious action; it is a 

 property dependent solely on the quantitative 

 relation. 



In contrast to a food let us consider the 

 action of an admittedly poisonous substance, 

 such, for example, as strychnine. It is poison- 

 ous because it increases the irritability of 

 motor neurons, so that even a small quantity 

 increases greatly the impulse resulting from a 

 given stimulus. Such an action is not advan- 

 tageous to the normal body; it is deleterious, 

 a poisonous action. If, now, the quantity of 

 strychnine be diminished till it no longer in- 

 creases the irritability of motor neurons, no 

 action advantageous to the healthful body re- 

 mains. The poisonous action in question is 

 one of degree, being greater with large amounts 

 and less with small but always exhibited, so 

 long as the quantity of strychnine is sufficient 

 to produce any effect. It is an essential qual- 

 ity of the strychnine and not one dependent 

 upon the quantitative relation. So long as 

 the strycluiine produces any effect at all it 

 exercises the kind of action which makes it a 

 poison. The essential quality of strychnine is, 

 therefore, that of a poison. It is a quality 

 exhibited in all quantities of strychnine ca- 

 pable of producing any definite action. To be 

 sure, there is a range of physiological adapta- 

 tion on the part of the body to an attenuated' 

 toxic effect within which no injurious action 

 is manifest; the quality of the action persists, 

 however, even in the diminished amount. The 

 quality which in amount is deleterious is es- 

 sential to strychnine and persists so long as 

 the quantity of strychnine suffices to produce 

 any definite action. 



In these examples we arrive at conclusions 

 that are of general application. An essential 

 quality is one that is exhibited by small 

 amounts of a substance capable of producing 

 any definite effect. Wlien a given quality of 



