« PreviousContinue »
WHAT THE SCIENCE TEACHER MAY DO TO HELP THE PROHIBITION OF THE ADULTERATION OF FOODS
PROFESSOR B. W. PEET, STATE NORMAL COLLEGE.
The conservation of natural resources is a term which is gradually coming to include human life as well as timber and coal. When we are told that nearly one-fifth of the sickness in the world is due to eating poisonous foods, that the consumption of opium in the United States, per capita, has more than doubled within the last forty years, that the consumption of cocain and other habit forming drugs is rapidly increasing and that the general health and efficiency of the human race are rapidly on the decline, we begin to think that a very important problem is before us to solve.
The adulteration of foods and drugs is almost as old as history. Every civilized nation has had to fight it but only within the last decade has it been recognized as a serious problem in the United States. Nearly every state now has a Food and Dairy Department whose business it is to analyze suspected foods and drugs and help protect the people from imposters. The platforms of the Democratic and Progressive parties each contained a plank urging better food and drug laws and President Wilson has many times made public utterances favoring more strict food legislation.
The passage of desirable laws through congress and legislatures is a slow and irksome process, especially when the public is so indifferent and the food and drug adulterators are so clever and go to any expense to sidetrack any legislation that will hurt their business. Publicity is the great lever to force the enactment of needed laws. Articles in magazines and newspapers help, but a campaign of education is needed and is the only way in which the matter will finally be solved.
Where shall we begin? The children in the grades could be taught many things, but the science teachers in our high schools are naturally the ones to interest themselves in the matter and direct the things that should be taught. They could give talks on adulteration of foods and drugs before their classes to begin with. Lecture demonstrations and laboratory experiments by the pupil showing methods of detecting adulteration are always interesting and educational.
The teacher could collect samples of canned goods on the market and teach the student to read the label and at the same time call attention to how the present laws protect us. As an illustration, sodium benzoate is considered by good authorities to be an undesirable and an unnecessary chemical preservative to put in foods, because it enables unscrupulous manufacturers to use decayed and waste fruit. The law allows its use in most states if so stated on the label. It is possible to buy ketchup and canned goods that do not contain it if one reads the label.
Jello is advertised in nearly every magazine and often in many brilliant colors to attract attention. By using colored powders one is led to believe that he can have strawberry jello one day, raspberry the next and a different fruit each day of the week, but careful reading of the label tells one that the color and flavor are artificial. It is surprising how many housewives use this and really believe they are serving geniune fruit jello. Why not buy the colorless gelatine and add the natural fruits and then have a wholesome article of food? (Show jelly glasses with label.)
The food laws are constantly being violated and attention should be called to the most common cases.
Saccharin is no longer allowed for sweetening foods, yet it is common to find it in soda fountain syrups, ginger ale, orange cider, pop and all soft drinks.
Ice cream in Michigan must contain 12 per cent butter fat and not more than one-half per cent thickening agent.
Hamberg steak is apt to contain sulphites and boric acid, especially during the hot weather. The preserving agent is sold and used under such names as “Freezum” or “Jerusalem” and the meat man will tell you it is used for cleansing, but it is very apt to get into the meat.
If the science teacher would collect samples of these products in his town and make tests before his classes the pupils would soon be educated as to what to buy and the storekeeper would learn to stock his store with pure products. Simple tests for these and many other preservatives and adulterants can be found in the references given at the close of this article.
Every year children are seriously poisoned by eating colored candy and often grown people are indisposed because of eating colored food. Seven aniline dyes are allowed by the government and in most states, but their toxic effect is questionable and as many people have been poisoned eating colored food and as it is unnecessary, I believe in teaching and urging them to leave color schemes out of foods and in warning children not to eat cheap colored candy. An interesting experiment is to extract the coloring matter from candy or cheap jam and show the aniline dye test by coloring white woolen cloth.
We must educate the people and finally our judges as to the seriousness of adultering foods and the selling of foods under a false label though the product itself is not poisonous. Listen to some of the United States court decisions :
Olive Oil found misbranded, fine $25.00.
Vinegar misbranded and adulterated-Ist fine $10.00; 2nd fine $25.00. Five firms were convicted four times for selling adulterated vinegar and are probably still in the business.
A few years behind the prison bars for a second offense would soon make it less tempting to violate the laws.
Another very serious problem is the drug-forming habit and the misbranding of patent medicines. This should be considered and proper warning given. The Department of Agriculture, Bureau of Chemistry, has a bulletin on the subject.
In every town there is usually an active women's club. A lecture on food adulteration before such an organization could be made intensely interesting and would bring practical results quicker than in any other way.
There is a desire just now to make science teaching more interesting and more practical. Is not here an opportunity to meet this desire and at the same time help in a needful work?
Detection of Common Food Adulterants. Bruce. D. Van Nostrand Co. $1.00.
Foods and Their Adulteration. H. W. Wiley. Blakiston Co., $4.00.
Pure Foods—Their Adulteration, Nutritive Value and Cost. John Olsen. Ginn & Co. Soc.
National Food Magazine, Monolith Bldg., 45 W. 34th St. New. $1.00.
Department of Agriculture; Bureau of Chemistry, Washington, D. C. Write for Bulletins. Free.
Reports of Dairy and Food Commissioner, Lansing, Mich. Free.
THE PREPARATION AND PROPERTIES OF PERMANENTLY
LIQUID SULFUR TRIOXIDE.
PROFESSOR D. M. LICHTY, UNIVERSITY OF MICHIGAN.
Sulfur trioxide has been known in a more or less pure or anhydrous state since its first preparation by Basil Valentine in the last half of the fifteenth century, by heating ferric sulfate, which yields sulfur trioxide and ferric oxide. Its preparation by heating fuming sulfuric acid was first described by Bernhardt in 1755. For upward of fifteen years or more, it has been made mainly by the contact process from sulfur dioxide and oxygen. All of these processes yield a product which, although possibly at first liquid, becomes at ordinary temperature solid and crystalline, in appearance much like asbestos. This is due to an action of sulfuric acid formed in small quantities by union of sulfur trioxide with moisture from the air.
Sulfur trioxide that is permanently liquid at ordinary temperature, seems to have been first made by Weber at Marburg in 1876, when he sealed the solid form into a tube bent at a right angle at its middle, and subjected it to repeated distillation and to alternate freezing and melting. The portions which did not melt rather readily, were separated from the liquid after each melting, until finally a residue was obtained that melted promptly and remained liquid at room temperature. By distilling the trioxide from phosphoric anhydride, he later prepared the liquid trioxide more easily.
My modification of this method consists in having the rightangled tube end in flasks, which permit the distillation of 100 cubic centimeters or more at a time, and in distilling under a pressure of 20 to 35 millimeters. Potassium sulfate was found to give as good results as the phosphoric anhydride. With the former the traces of sulfuric acid in the trioxide evidently produce potassium hydrogen sulfate, stable at the temperature of distillation (35° or less), while the latter dehydrates the sulfuric acid producing metaphosphoric acid and sulfur trioxide.
The melting point of the permanently liquid sulfur trioxide is 16.8° C. Its boiling point under normal atmospheric pressure is not above 44.9° C. Supercooling to 12 or even to 10° may be necessary before it freezes, and then the whole mass usually becomes crystalline in a moment. Although the critical temperature of sulfur trioxide is at or near 216° C., its coefficient of expansion at ordinary temperatures is 0.0027, i. e., about threefourths of that of gases (0.00366), and is very high as compared with that of liquids generally. Its density is 1.923 at 20° C. and decreases rapidly (Cf. coefficient of expansion) with rise in temperature, falling to 1.792 at 48° C.
The molecular weight of its vapor is 8o, agreeing with the formula SO, and also with the molecular weight of the vapor from the ordinary
solid trioxide. In its solution in phosphoryl chloride the depression of the freezing point is such as to lead to the same value for the molecular weight, namely, 80, whether one has dissolved the liquid or the solid trioxide. Oddo has published data which lead to 160 (8,00) as the molecular weight of the solid trioxide when dissolved in phosphoryl chloride. The speaker could not substantiate Oddo's results.
If the purifying apparatus is left in an inverted position, i.e., so that the receiving flask will empty its contents back into the distilling flask, crystals will usually form all over the inner surface of the former, even though the trioxide has been distilled from the anhydride of phosphorus into the receiver twenty times and the walls of the latter have been rinsed off thoroughly after each distillation.
If the trioxide has been distilled from potassium sulfate until it remains liquid at ordinary temperature, and is then left in the receiver, crystals will form in a short time around the potassium sulfate, the quantity growing and the volume of liquid in the receiver decreasing. The crystals seem to form directly from the vapor, and in time all the liquid will have disappeared from the receiving flask and have been converted into crystals in the distilling flask. This change occurs even if the whole apparatus is immersed in a thermostat at constant temperature.
If the wall of a vessel, whose inner surface is moist with sulfur trioxide, is gently warmed, there appears on it a thin coating of crystals which vaporize when warmed more intensely. The first effect is like that of evaporating a solution.
At the sealed off ends of the necks of several vessels in which liquid sulfur trioxide has been enclosed, there appeared after some time small amounts of crystals. In one or two instances, the quantity of crystals grew large enough so that by washing them partly loose by means of the liquid, they extended into the latter but did not appear to increase in quantity. We have here the case of a solid, a liquid and a gas phase existing simultaneously at different temperatures, which is contrary to the phase rule. Evidently these three phases are not related to one another as ice, water and water vapor are, for these can exist side by side at but one temperature.
Before closing, it may be wise to remark that, when distillation is carried out in a sealed apparatus, the heating of the distilling flask and the cooling of the receiver must be so regulated that the internal pressure will not cause an explosion. It is easily possible to cool so efficiently that the material boils well below the temperature required to boil it in air, and that therefore the internal pressure is no source of danger. This method of distilling has been successfully applied both to concentrated sulfuric acid
and to mercury.