394 
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 physiological effects of such substances as common 
salt, sodium bicarbonate, 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 dis- 
cussed from practically every standpoint. A priori, most of us would 
probably 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 (25) 
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 be harmless 
to the vital processes of the higher animals; (2) numerous clinical 
observations have been recorded which show that dyspeptic and 
other troubles follow the use of foods which have been treated with 
preservatives ordinarily employed for such purposes, such as borax; 
(3) even if as in the case of boric acid and borax, the poison is 
not cumulative, the continuous passage of foreign substances through 
the kidneys can not be beneficial to those organs. A similar stand 
against the use of preservatives in food has been taken by Leffmann 
(58). According to this author, the bad effects of a food preserva- 
tive may show itself in several ways: (1) It may interfere with the 
action of the digestive ferments, as has been proven in the case of 
salicylic acid; (2) it may act on the food, like formaldehyde; and (3) 
it may work a direct injury to the body as is known to be the case 
with almost all mineral preservatives. Hope (59) looks upon it as 
