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all forms of cells, and for protoplasm generally, but states that no 
satisfactory explanation of its toxicity is yet known. Kastle and 
Loevenhart (54) found it highly toxic to lipase, the fat-splitting fer- 
ment, and quite recently Loevenhart and Pierce (55) have consid- 
erably extended these observations, and have found that sodium 
fluoride retards the action of lipase when present in a solution of the 
ferment at the great dilution of one to one hundred million. 
Baldwin (56) has called attention to several cases of accidental 
poisoning with sodium fluoride that came under his observation, in 
which an insecticide consisting of sodium fluoride was mistaken for 
baking powder and used in the making of griddlecakes. In these 
cases violent vomiting and purging followed quickly after the eating 
of these cakes, which probably contained rather large amounts of the 
fluoride. These observations led the author to test the toxicity of 
sodium fluoride on himself. He found that 0.03 gram of sodium 
fluoride, eaten with bread, produced no effect. Neither did 0.09 
gram taken a little later. 0.25 gram taken on an empty stomach 
produced nausea in two minutes, which effect reached its maximum 
in twenty minutes. During this time there was an increased flow 
of saliva and retching, but no vomiting. In about two hours these 
symptoms had subsided. Luncheon was then eaten, but without 
relish. Vomiting occurred immediately after eating, and slight 
nausea continued throughout the day on which the poison was taken. 
Baldwin concludes from his observations that sodium fluoride 
belongs to the class of less violent poisons, the characteristic symp- 
toms being nausea, vomiting, and salivation. 
According to Van Slyke (57) potassium dichromate is not a very 
violent poison, though not entirely harmless. Concerning the phys- 
iological effects of such substances as common salt, sodium bicar- 
bonate, etc., nothing need be said in this connection. 
It is evident therefore that those who have made the closest study 
of the use of preservatives in food are very much divided in their 
opinion regarding the possibility of ill effects resulting from their use. 
Indeed the whole subject of food preservatives has been discussed 
from practically every standpoint. A priori, most of us would prob- 
ably be inclined to proceed on the assumption that a substance 
which is toxic to micro-organisms is also toxic to the cells com- 
posing the tissues of man and the higher animals. In his testimony 
before the food-preservatives committee, London, Halliburton (24) 
took the stand that the use of food preservatives should be abandoned 
and methods of cold storage and transportation substituted in their 
place, upon the ground (1) that an antiseptic which is inimical to the 
life of those organisms that cause putrefaction can not therefore be 
