COPPER-GREENING IN FRANCE. 1065 



heated to 45 for eighteen hours. At the end of this time the fibrin was entirely dis- 

 solved. Those experiments did not allay the scruples of our colleague, who claimed 

 justly that the experiments did not settle the question of the digestibility of the 

 vegetables in question. A new set of experiments was then made with great care by 

 M. Ogier to determine the comparative digestibility of vegetables greened with cop- 

 per as compared with those not so treated. M. Ogier concluded that there is nothing 

 to indicate that the digestibility of greened vegetables is less than that of those 

 "au naturel." 



Among the facts furnished by our work are these : 



That the quantity of metallic copper contained in green legumes of commerce is 

 about 13 mg per kilo; that with 10 mg they are sufficiently colored, and that 40 

 mg impart a taste which renders them inedible. 



We propose that the Coinite cousultatif reply to the minister that it is of the opinion 

 that in view of the present state of our knowledge of the toxic effects of the salts of 

 copper, it is not necessary to interdict the process of greening with salts of copper. 



The report was approved by the Comite" consultatif d'hygiene on 

 April 15, 1889. 



On April 18 a ministerial circular was issued, raising the prohibition 

 on the use of copper-greening for preserved foods, directed to the vari- 

 ous prefects. It read as follows : 



Three ministerial circulars (1) December 20, 1860; (2) May 20, 1881; (3) June 20, 

 1882 have been addressed to the prefects instructing them to take action to prevent 

 manufacturers, merchants, and retailers from employing vessels or salts of copper in 

 the preparation of preserves of fruit and legumes destined for alimentation ; also to 

 prevent selling or offering for sale goods thus prepared. 



This prohibition was based upon the repeated statement of the Comite" consultatif 

 d'hygieue publique of the danger of poisoning from the introduction of copper sul- 

 phate in frequently repeated doses into the human system. 



The action in such cases of salts of copper upon health had not at that time 

 received the careful study which has since been given to the subject. 



In the last few years new studies and extended experiments which have been now 

 brought to a successful close, have resulted in the establishment of facts hitherto 

 doubtful. 



The question having been submitted anew to the Comite" consultatif d'hygiene 

 publique, it has also conducted experiments to determine the dose which can be 

 safely ingested and the proportion contained in copper-greened vegetables. 



From this it has been concluded that the recent knowledge acquired was of such 

 a convincing nature as to justify them in no longer opposing copper greening. 



I have the honor, therefore, to call your attention to this conclusion. 



In order to promote the interests of commerce and to render to it the satisfaction 

 so long denied, it is for you to take action conformable to this circular. Let the 

 necessary measures be taken without delay, and let information of the execution of 

 the order be transmitted. 



Nothing is said in this circular relative to the distinction between 

 the two classes of goods which was proposed by Grimaux possibly 

 because it would not look well upon the records. The matter may have 

 been left to the discretion of the prefects. In the samples of canned 

 vegetables examined in this laboratory, those French goods marked 

 "au naturel" always contained copper, and though those marked "a 

 1'anglaise" usually did so also, there was one which did not, the pea 

 sample No. 10629. This sample, however, contained a large amount of 

 zinc, as a compensation. 



