616 



SCIENCE. 



[N. S. Vol. XXI. No. 538. 



themselves as harmful. In the latter case 

 there must be an abundant justification on 

 the part of the user to excuse their intro- 

 duction. I think we may assume, for the 

 purposes of this argument, that copper sul- 

 phate is in itself an injurious substance. 

 This does not relate to its use in a medicinal 

 sense. It is well known that the great 

 majority of drugs which are used in disease 

 are not harmless to health ; in other words, 

 the fact that any given substance may be 

 used as a remedy in disease is no justifica- 

 tion whatever for its use by persons in 

 health. 



The fact that a substance may be nat- 

 urally found in a food product accidentally 

 or otherwise, which in itself is harmful, is 

 no excuse for adding more of the substance 

 to the food product. For instance, hydro- 

 cyanic acid is found in certain food prod- 

 ucts, such as peaches and cassava ; borax 

 is found almost uniformly in grapes and 

 wines; benzoic acid occurs in considerable 

 quantities in cranberries, and copper is 

 occasionally found in some food products 

 in weighable quantities. It requires no 

 argument to show that the accidental pres- 

 ence of bodies of this kind is no justifica- 

 tion whatever for adding additional quan- 

 tities thereto. In other words, foods them- 

 selves are often injurious, but that does not 

 imply that more injurious substances 

 should be added to them. The attitude of 

 experts in regard to these matters is the 

 most puzzling problem of all. Men of equal 

 honesty, equal ability and with equal skill 

 as experimenters entertain diametrically 

 opposed views on these subjects. It ap- 

 pears that the one safe position each lay- 

 man can take in the matter is to demand 

 protection from being compelled, without 

 his knowledge, or even with his knowl- 

 edge, to consume substances in foods 

 which a very respectable part, or per- 

 haps even a majority of expert evidence, 

 condemns. The right of any one to con- 



sume antiseptics and coloring matters in 

 his food should not be denied, but it is not 

 fair that those who hold a contrary opinion 

 should find it almost impossible to secure 

 food products devoid of the substances to 

 which he objects. This principle, it appears 

 to me, applies particularly to water, which 

 is a substance of universal consumption. 

 The principal excuse for the use of a sub- 

 stance like sulphate of copper, aside from 

 the effect which it has on the living organ- 

 isms in the water, is found in the state- 

 ments which have been made that no cop- 

 per remains in the water. Any residual 

 quantity remaining, be it ever so small, is 

 objectionable. The argument de minimis 

 is in my opinion wholly fallacious. 



A very full discussion of the subject of 

 the presence of copper in foods is found in 

 the report of the committee on food pre- 

 servatives, presented to both Houses of 

 Parliament by command of the King in 

 1901. The report was signed by Herbert 

 Maxwell, chairman, T. E. Thorpe, H. Tim- 

 brell Bulstrode and F. W. Tunnicliflt'e. On 

 page XXX, article 136 of this report, section 

 F, under recommendations, it is stated 

 'That the use of copper sulphate in the so- 

 called greening of preserved foods be pro- 

 hibited. ' This part of the report, it is but 

 fair to say, was not concurred in hy Mr. 

 Tunnicliffe. After stating his reasons for 

 not signing the recommendation as given, 

 he states, page xxii: "I am, however, sat- 

 isfied that often an unnecessarily large 

 amount of copper is present in vegetables 

 permanently colored by means of it, and 

 although in spite of diligent investigation 

 no injurious results have been known to 

 have occurred even from these quantities, 

 yet, nevertheless, onJy the necessary amount 

 should be added. I should, therefore, 

 recommend that the presence of copper in 

 these preserved vegetables be in every case 

 declared and that its amount be restricted 



