10G8 FOODS AND FOOD ADULTERANTS. 



Bartli recalled the Brunswick trial, and remarked that the accused in this case had 

 been acquitted, as in the opinion of the court he had not used copper to conceal the 

 condition of damaged goods, and also the amount of copper present and the form in 

 which it occurred were not injurious. He hoped that the society would declare 

 that in its opinion the use of small amounts of copper to color vegetables should not 

 be condemned. It ia a positive fact that for this class of goods some kind of color- 

 ing agent is a necessity. Vegetables, especially peas and string beans, retain their 

 natural green color on simple cooking in open vessels, but when heated in the sealed 

 can, become yellowish or brownish and are unseemly in color. Peas can be toler- 

 ably easily colored with various vegetable colors, but this is not the case with beans. 

 Copper salts are administered as emetics in doses as high as a gram, and he had seen 

 the fatal dose given as 10 grams. These, however, were amounts which were far in 

 excess of anything which could possibly be taken with canned goods. To his knowl- 

 edge chronic copper poisoning was unknown. Cows had been given doses as high 

 as 8 grams of copper sulphate daily without bad result. 



Dr. G. Merkel agreed with the previous speaker that acute poisoning from large 

 amounts of copper could not occur from the use of copper salts for coloring canned 

 vegetables. Chronic copper poisoning had not been proved. The cases in the liter- 

 ature could not stand a severe criticism. He himself had lately given some attention 

 to the subject, and had come to the conclusion that the state of knowledge of the 

 toxicology of copper is defective. In the course of a long experience as a hospital 

 physician he had observed no case of chronic copper poisoning, although if it 

 occurred at all it should not be rare. In the trades having to do with copper 

 chronic copper poisoning has not yet been observed. On the other hand, it is not 

 yet possible to say that the metal is harmless. The state of the copper occurring in 

 the different canned foods has a bearing on the question. It is quite possible that 

 small doses of copper if repeated for some time might, under some circumstances, 

 prove dangerous, but he was not prepared to state what these circumstances might 

 be. It was dangerous to attempt to draw conclusions in regard to the human sub- 

 ject from the results of experiments upon the animal. He was opposed to applying 

 the pharmacopoeia to food chemistry. At present he did not regard the question as 

 decided, aad was of the opinion that medical men should wait for further results 

 before committing themselves. 



Kayser spoke of the danger of rushing from one extreme, according to which copper 

 salts have been regarded as dangerous, to the other and calling them harmless. 

 Preserved foods are not merely an occasional article of diet, but in many instances 

 form an exclusive food for considerable periods of time. He was of the opinion that 

 it was not yet time to form an opinion. 



Dr. Egger said that at present it could not be said definitely what amount of cop- 

 per was dangerous. Much depends upon the individual. He was of the opinion 

 that it would be a good thing to establish a maximum limit. 



Mayrhofer remarked that the question was not one of soluble copper salts, to 

 which Kayser retorted that the question involved such solvents as gastric juice and 

 not water or dilute hydrochloric acid, and inquired if Mayrhofer and the canners 

 were ready to guarantee that the 20-24 mg limit should not be overstepped. 



Mayrhofer answered that in making some dyeing experiments with peas two sam- 

 ples were colored to nearly the same shade, and absorbed, respectively, 18 and 24 mg. 

 In two other experiments the coloring was pushed till the peas had a marked blue 

 shade. The amounts absorbed were, respectively, 32 and 44 mg. Coloring in this 

 way (with copper salts), the risk of such amounts as he had found in the chlnois 

 sample coming into the goods was quite excluded. On inquiry into this case ho had 

 found that the large amount (76 mg) was due to the fact that the fruit had been 

 allowed to stand several days in a copper pan. This, however, was an accident and 

 such cases must be rare. In his coloring experiments he had found the minimum 

 amount of copper with which the desired color could be obtained to be 17 mg. 



