322 WILEY— INFLUENCE OF PRESERVATIVES [April 25, 



as a food preservative would be especially inadvisable in milk or 

 cream, because its addition in dilute solution prevents the growth 

 of acid-forming bacteria, but has no effect in retarding the action 

 of many harmful organisms; in other words, the milk is prevented 

 from becoming sour and thus indicating its age and the danger sig- 

 nal is thus removed, while the other organisms which are capable 

 of producing disease continue to multiply in the milk with practically 

 the same degree of rapidity as if the formaldehyde was not present. 



The final conclusion, therefore, is that the addition of formalde- 

 hyde to foods tends to derange metabolism, disturb the normal func- 

 tions, produce irritation and undue stimulation of the secretory 

 activities, and, therefore, it is never justifiable. 



Sulphate of Copper. — The data which have been collected in the 

 course of this experiment have led to the conclusion that the 

 administration of sulphate of copper even in the extremely small 

 quantities in which it has been given has a very distinctly unfavor- 

 able effect upon health and digestion, as indicated by the ordinary 

 clinical and medical summaries. Severe pains are produced in the 

 stomach accompanied often with nausea and sometimes with vomit- 

 ing, there is a general tendency to malaise, often a development of 

 headache, and other unfavorable symptoms of a more or less per- 

 sistent and uniform character. Further than this, the symptoms 

 which arc usually not developed for about a week continue in some 

 instances for a number of days into the after-period after the sul- 

 phate of copper has been withdrawn. The data indicate that cop- 

 per, like many other metals, is likely to produce a cumulative effect, 

 and that its administration in even much smaller quantities than 

 those indicated, or less than those which would be ingested in the 

 regular consumption of coppered vegetables, is attended with more 

 or less danger on this account. 



There was a very small loss of weight in nine of the subjects, 

 while the three who showed the greatest tolerance of the copper 

 sulphate gained in weight. No definite conclusions can, therefore, 

 be formed respecting the general effect upon the weight of the 

 body, except that in the cases where uniform effects ar& produced 

 there is a slight loss of weight. 



The copper salt which was used in this experiment differs from 



