T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
3 60
A sample of No. 6 ; 109-1 13 O , was easily and smoothly converted into trinitrotoluol ( T N T ) , according t o the method recommended by H0ffmann.l T h e crude product, washed with hot water, melted a t 76-78O. After one recrystallization from a mixture of alcohol (9 parts) and benzol ( I part), pale yellow needles, melting sharply a t 80-80.5 O , were obtained in excellent yield. EXPERIMENT I1
88.5 g. cymol, 885 g. benzol and 4.5 g. aluminium chloride were boiled together on a water bath for I O hrs. A 3-section Young still head was used in t h e first fractionation and a j-section Young still head in the second. Fraction NO.
1..
...
2.....
3..... 4.. , 5.. G.....
.. ...
Temperature Interval 79- 810 81- 83: 83- 95 95-110' 110-13lo 131-141'
Volume Cc. 501 299 15 1 21 16 16
Fraction Temperature Volume No. Interval cc. 11 7 . . . . . 141-151' 8.. 151-154° 37 15 9 . . . . . 154-170° 3 l o . . . . . 170-180; 2 l l . . . . . 180-200 12 2000+ 3
.. .
.....
For the second distillation, Fraction No. started with.
2
Fraction
Volume Cc.
No.
Temperature Interval
Volume cc. 249 126 62 6 22
8
Fraction No. 7..
... s..... 9..... 10.. * . 1 1 .... 1 2 . . . ..
Temperature Interval
was
*
The accumulations again show toluol and cumol. The amounts are less in both experiments t h a n those claimed b y Boedtker and Halse. They gave no statement as t o the purity of their products so t h a t question is in doubt. On our part some necessary step may still be lacking for maximum yields. T h e investigation is being actively pursued. Boedtker and Halse introduced in each of their experiments two variants so t h a t i t cannot be said which variant changed the results. I t will be noted t h a t 17 molecules of benzol were used for one molecule of cymol. I t is hoped t o materially reduce this proportion. The mechanism of the reaction will be studied in order t o determine whether the cymol furnishes the methyl or the tolyl group for the toluol. It is noted t h a t the published work on the nitration of cymol and of cumol is of a n unsatisfactory character and these reactions are being re&xa mined. CONCLUSIONS
Spruce turpentine yields toluol when subjected t o t h e combined action of benzol and aluminium chloride. The other product, cumol, is not a waste product since it may be oxidized directly t o benzoic acid. This will save a like amount of toluol now used t o make benzoic acid. UNIVERSITY OF NORTHCAROLINA CHAPELHILL, N. C.
ARSENlC IN SULFURED FOOD PRODUCTS By W. D. COLLINS Received January 10, 1918 INTRODUCTION
I t has been recognized for a long time t h a t appreci.able quantities of arsenic might be taken up by food 1
Bureau of Mines, Technical Papev 146 (1916).
Vol.
IO,
No. 5
products through treatment with sulfur dioxide fumes obtained by burning sulfur which contained arsenic. The most notable case of contamination of food products with arsenic was t h e well-known instance of poisoning a t Manchester, England, caused b y arsenic in beer. The investigation t h a t followed showed t h a t the arsenic in t h e beer came from the use of glucose or brewers' sugar which was made from starch by the use of sulfuric acid which contained large amounts of arsenic. Analyses of some of t h e samples. of sulfuric acid showed as much as 2 per cent of arsenic as As208. Samples of the glucose contained from 0.01 up t o nearly 0.1 per cent of arsenic. Samples of the beer in question contained up t o 1.0 or 1.5 grains of arsenic per gallon of beer, and some even as high as 3 grains per gallon. The average medicinal dose of arsenic mentioned in t h e U. S. Pharmacopoeia is 2 mg. or one-thirtieth of a grain. I n the report of the English Commission which investigated these cases of arsenical poisoning, it was recommended t h a t liquid food materials should be considered adulterated if they contained as much as 0.01 of a grain of arsenic per gallon, and t h a t solid food materials should be considered deleterious if they contained as much as 0.01 grain of arsenic per pound. The results of the investigation showed t h a t it was entirely possible to keep the arsenic below these limits in all the materials used in the production of t h e beer and in the other food materials which were investigated a t t h a t time, provided care was taken t o keep the materials free from arsenic. I n connection with a n investigation of t h e subject of arsenic in wines, Dr. H. D. Gibbs,l in 1905,suggested arsenical sulfur as one of the possible sources of arsenic. Several samples of the Japanese sulfur which he examined showed amounts of arsenic up t o several hundred parts per million. Dr. W. W. Stockberger,2 in a bulletin published in 1908, suggested t h a t sulfur was probably the cause of the presence of appreciable amounts of arsenic in certain samples of sulfured hops. It appears t o be recognized by the dealers in sulfur t h a t i t is desirable t o use for bleaching hops and dried fruits sulfur which is free from arsenic. I t is probable t h a t certain users of sulfur have made some effort t o obtain sulfur which contained no arsenic. I n 1914, as a result of objections made t o some shipments of hops from the United States t o foreign ports on account of the fact t h a t the hops were said t o contain more arsenic t h a n was ,permissible, the Department of Agriculture investigated again t h e question of the source of arsenic in dried hops. Dr. Stockberger, of the Bureau of Plant Industry, visited the hopgrowing districts and collected samples of unsulfured hops, sulfured hops and samples of the sulfur used. He also collected samples of sulfur used on the hops in the shipments which were rejected on account of excessive arsenic. Two samples of sulfur from this lot showed 329 and 356 parts of arsenic per million. The writer made a study of various methods for the determination of small quantities of arsenic in such 1
2
41-46.
J . Am. Chem. Soc., 21 (1905), 1484-96. U. S. Dept. of Agr., Bureau of Plant Industry, Bull. 121 (1908),
May, 1918
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
materials as hops and sulfur and after reaching a satisfactory method, as described below, determined t h e arsenic in samples of sun-dried hops, kiln-dried hops and sulfur.’ METHOD O F ANALYSIS
The use of the Gutzeit test for the quantitative determination of arsenic has been discussed by Sanger and Black,2 Smith,s Allen and Palmer.‘ and recently by Beck and Merres6 of the Kaiserlichen Gesundheitsamt who found Smith’s method entirely reliable. Many references t o t h e literature are given by these authors. On account of t h e difficulties found in applying t h e various methods described, it seems worth while t o describe fully t h e details of t h e method found satisfactory for the examination of hops. It is mainly a selection of some of the procedures described by C. R. Smith. O U T L I N E O F METHOD
The method depends upon the action of arsine upon a salt of mercury. The arsine is produced b y reduction of a n arsenious compound by nascent hydrogen obtained with zinc and an acid. I n t h e colorimetric method the arsine acts along a strip of paper impregnated with mercuric bromide, and t h e amount of arsenic is measured by t h e brown color produced. I n t h e gravimetric method the arsine acts on mercuric chloride in solution and t h e mercurous chloride obtained on boiling is weighed. PRECAUTIONS
To obtain consistent results in the colorimetric method where comparison is made with standard stains, it is essential t h a t the rate of evolution of hydrogen and of arsine be the same in all cases for a given amount of arsenic. Smith recommends cooling the generator in making standard stains t o obtain results comparable with those obtained with samples containing salts in solution. Allen and Palmer advise using more acid when salts are present. Smith’s precipitation method seems more certain t o give a uniform amount of salts in the generator. The arsenic is precipitated as ammonium magnesium arsenate together with ammonium magnesium phosphate by adding about 2 g. of a soluble phosphate t o t h e solution of sample and then precipitating with magnesia mixture and ammonium hydroxide. This precipitate is large enough t o mask small differences in t h e amounts of salts so t h a t solutions for standard strips and for the samples will have practically the same conditions in the generator if t h e same amount of acid is used t o dissolve t h e precipitate. I n testing substances which will give a precipitate in ammoniacal solution with t h e ammonium magnesium phosphate, allowance must be made for t h e extra amount of salts which will be in the generator. I n order t h a t t h e rate of evolution of arsine may be t h e same in all cases, it is necessary t h a t t h e arsenic be reduced t o the arsenious condition before zinc is 1 The detailed results of the analyses are given in U. S. Dept. of Agr., Bull. 568, “The Presence of Arsenic in Hops ” W. W. Stockberger and W. D. Collins 2 J . S o r Chem. I n d , 26 (1906), 1115. a U.S. Dept. of Agr., Bureau of Chemistry, Circular 102 (1912). 4 Orig. Corn. 8th Inter. Con2 A p p l Chem , 1 (1912). 9-17. 6 A r b kazs. Gesundh., 50 (1916), 38-49.
36 1
added. The choice of reducing agent and of acid depends upon the amount of arsenic present, and for t h e best results t h e proper combination must be selected. When hydrochloric acid is used in t h e generator it is not easy t o secure sufficiently slow evolution of gas t o make a strongly colored stain if enough acid is used t o complete t h e reduction of the arsenic. This difficulty is overcome by using sulfuric acid, but if potassium iodide and stannous chloride are used for reduction with sulfuric acid, it sometimes happens t h a t reduction of sulfuric acid t o hydrogen sulfide takes place and t h e determination is lost. I t is possible, however, t o fail t o reduce all the arsenic t o the arsenious state without the use of potassium iodide if much more than 0.1 mg. of arsenic, as AsZ03, is present. For small quantities, reduction with stannous chloride (0.5 g.), with I g. sodium chloride and I O cc. sulfuric acid in a volume of 7 5 cc., gives consistent results. For larger quantities which are t o be determined gravimetrically, so that t h e rate of action need not be the same in every case, reduction by stannous chloride and potassium iodide in hydrochloric acid solution is best. The surface area of the zinc will affect the rate of action. Care must be taken t o use always t h e same number of pieces of zinc of t h e same size. The amount of iron in the zinc will affect t h e rate of solution and, therefore, t h e appearance of the stain. The capacity of t h e apparatus and the amount of liquid used in the generator will affect the appearance of the stain. For obtaining a test for a very small quantity of arsenic, as t o distinguish between 0.5 and I microgram, it may be best t o use a small generating bottle; but for quantitative measurement of amounts from 5 to 5 0 micrograms a larger generator gives more uniform results, though the time required is longer. The temperature of t h e reaction affects not only the rate of evolution, but, as pointed out by Allen, t h e temperature determines t h e amount of moisture in the gas evolved and so affects t h e appearance of the stain. Differences of one or two degrees in temperature are not likely t o have any measurable effect on t h e stains, but as much as 10’ may have a decided effect. APPARATUS
The accompanying diagram shows t h e form and dimensions of the apparatus used. REAGENTS
THE SENSITIZED STRIPS O F D R A W I N G P A P E R , 11 cm. long b y 2 . 0 or 2 . 5 mm. wide, are prepared by soaking for one hour in a 5 per cent alcoholic solution of mercuric bromide. The excess solution is wiped off and the strips dried on glass rods. ACIDS A N D ZINC may be purchased practically free from arsenic. SODIUM CHLORIDE is usually free from arsenic, but samples of reagent sodium chloride have been found to contain measurable amounts. S T A N N O U S CHLORIDE is liable t o contain traces of arsenic. This can be removed by heating the solution of t h e salt in hydrochloric acid with pieces of metallic
362
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
tin and a piece of platinum wire or foil. Heating t h e solution for several hours will usually remove t h e arsenic. The solution is diluted, filtered, and made t o such a volume t h a t I cc. contains 0.5 g. stannous chloride. -Drawing paper 2 2 x 1 1 0 T H E S O D I U M OR A M M O N I U M mm soaked 1 hour in 5 per cent alcoholic mer- P H O S P H A T E S found in t h e curic bromide and dried
laboratory may contain arsenic. The microcosmic salt used in examining hops was purified by making a concen~ wool l molsteneq ~ ~ trated ~ solution strongly acidiwith per cent lead fied with hydrochloric acid, acetate solution adding mercuric chloride solution and passing in hydrogen sulfide gas t o saturation. The solution was left about 2 4 hrs. -F’llter paper wet with ~;;;~~~~eadd,i.~tate so- with occasional stirring by a stream of hydrogen sulfide. The precipitated mercuric sulfide, which carried with i t the arsenic as sulfide, was filtered -Level of liquid out. The solution was boiled -20 CC. concentrated t o remove hydrogen sulfide, sulfuric acid in 120 cc and bromine water was added in slight excess. After filtering, if necessary, t h e volume FIG I-APPARATUS FOR THE was made such t h a t I O cc. GurzErT AS contained z g. of the microFIED BY C. R. SMITH cosmic salt. M A G N E S I A MIXTURE-The general laboratory stock of magnesium salts are liable t o contain arsenic. This can be eliminated by treating a solution of the salt with hydrochloric acid and arsenic-free zinc. The reaction may be allowed t o proceed for a day, with gentle heating. After filtration ammonium hydroxide and hydrochloric acid are added alternately till there is no precipitate when the solution contains a n excess of ammonia. The volume is adjusted so t h a t a convenient amount, 15 or 2 0 cc., will give a n excess when used t o precipitate 2 g. of the phosphate. VEssELs-It is generally known t h a t arsenic may be taken up from some glass vessels by solutions, especially when heated. It is advisable, therefore, t o use porcelain, as far as possible, for heating solutions t o be tested for arsenic. Tests of solutions of reagents soon after treatment t o remove arsenic rarely gave any indications of the presence of arsenic, while after standing a month in flasks t h e same solutions often showed measurable amounts of arsenic, which may have been absorbed from t h e glass. STANDARDS
With all precautions there will still be some irregularity in the length of stains due t o variations in width of paper strip, in size and condition of pieces of zinc, in volume of solution, strength of acid, volume of air space above solution in generator, in size of tubes holding lead acetate paper and moistened glass wool, possibly also in the sensitiveness of t h e paper. All these possibilities of error are covered by Smith in t h e suggestion t h a t at least three concordant stains should be
Vol.
IO,
No. 5
obtained before a value is selected. I n testing a number of samples of hops over several weeks’ time, it was found advantageous t o make a few standard stains each day with the day’s lot of samples. Portions of standard arsenic solution were treated with bromine t o oxidize t h e arsenic and t h e solution so prepared was treated in exactly the same manner as the solutions prepared from the samples. At t h e end of t h e experiments a number of standard strips had been made covering all the range of values which had been f.ound. The end of t h e brown stain on each side of a strip was marked t o the nearest millimeter and t h e average of the lengths on both sides was taken as the length of stain corresponding t o the amount of arsenic which was precipitated. The accompanying curve, which shows all t h e values obtained for standard stains, shows the relation between t h e length of stain and t h e amount of arsenic, and indicates t h e errors which may be made in single determinations.
c.
R. SMITH’S
COLORIMETRIC
M E T H O D APPLIED
T O HOPS
To determine arsenic in hops the samples were oxidized carefully in porcelain casseroles with concentrated nitric and sulfuric acids. After t h e vigorous action with nitric acid was over, sulfuric acid was added and oxidation completed by heating over a small flame with additions of small amounts of nitric acid till fumes of sulfuric acid were given off with no blackening of the solution. As has been pointed out by various writers, arsenic will be reduced and lost if t h e organic matter chars and t h e solution gives off sulfur dioxide. 90
Y
0
I
4
/O
I
2G
I
3G
, 40
I
I
I
50 70 M E m M s Asp o3
,
80
I
90
I
/W
//A
FIG. 11-RELATIONJBETWEEN AMOUNTS OF ARSENIC ’AND LENGTHOP STAINSOBTAINEDIN ONE SERIESOF TESTS
Small amounts of bromine water were added t o make sure of the oxidation of t h e arsenic. The arsenic was precipitated by the use of z g. of microcosmic salt, a n excess of magnesia mixture and ammonia t o complete t h e precipitation. After standing over night t h e precipitate was filtered, washed once with 2.5 per cent ammonia, and then dissolved in about jo cc. of dilute sulfuric acid containing I O cc. of t h e concentrated acid. After solution of t h e precipitate and washing of t h e filter, t h e volume was about 7 5 cc. One gram of sodium chloride was added and t h e solution heated nearly t o boiling, about g o o C. One CC.
May, 1918
'
T H E JOURNAL OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
of solution containing 0.5 g. stannous chloride was added and the warm solution stirred occasionally for I O min. The solution was now cooled, I O cc. more of concentrated sulfuric acid added and the mixture again cooled. The liquid was now transferred t o a 4-01;. bottle and made u p t o a volume of about 1 2 0 cc. When t h e stopper was in place the air space was about The bottles were placed in a pan of water and 20 cc. brought t o a temperature of zoo C. Four pieces of stick zinc were now added. Two pieces were new and were 18 mm. long and 7 mm. in diameter. Two of t h e pieces had been used in previous determinations. The stopper carrying t h e tubes with the lead acetate paper, glass wool saturated with lead acetate, and t h e mercuric bromide paper were put in place immediately after the addition of zinc. Practically all of the stain was formed in one hour, but t h e strips of paper were regularly left for 3 hrs. The samples of hops were divided into portions of about 18 g. I n order t o eliminate errors from the presence of arsenic in reagents and vessels, a sample of one gram of hops was digested with the same amounts of sulfuric and nitric acids and bromine as were used for the 18-g. sample. The digestion mixture of each sample was filtered. T h a t from the 18-g. sample was made u p t o 2 0 0 cc. and volumes of the zoo cc. solution were taken corresponding t o I g., 6 g. and 11 g. Thcse aliquots were precipitated in t h e same manner as the solution from t h e digestion of the I-g. sample. After the stains were made by treating these samples in the generator, the lengths were measured. The difference between the length of the stain for the I-g. sample and the stain obtained for '/la of the 18-g. sample indicated the amount of arsenic obtained from t h e digestion reagents. By reading on the curve the amounts of arsenic corresponding t o the stains obtained for the I-g., 6-g. and 11-g. sub-samples, any error from the reagents used in precipitation could be eliminated. The difference between the 6-g. sample and the I-g. sample was taken as the amount of arsenic in j g. of hops, and t h e difference found between the 11-g. sample and the I-g. sample was taken as the amount of arsenic in I O g. of hops. About 1000 tests were made in the course of this work and the treatment outlined above gave in nearly all cases satisfactory stains of which the length could be measured with certainty and the results which were obtained leave little doubt as t o the amount of arsenic present in the samples which contained a s much as 0.5 p. p. m. The average of several concordant results is probably within I O per cent of the true value for quantities of 3 or 4 p. p. m.; the samples contained as little as 0.1 or 0.2 p. p. m.; the amount of arsenic obtained from t h e reagents and vessels used in the work was greater t h a n t h a t present in the sample, so t h a t there is some uncertainty as t o whether t h e amount reported as 0.2 really means any arsenic a t all. If it were desired t o settle the question as t o whether the sample taken contained no arsenic or 0.1p. p. m., it would be worth while t o spend more time in making sure of the purity of the reagents.
3 63
ARSENIC I N SULFUR
To determine t h e arsenic in samples of sulfur, I t o I j g. of sulfur were treated with from 5 t o z j cc. of bromine as described by W. Smith' for the estimation of selenium in sulfur. The sulfur bromide and bromine were shaken cautiously in a separatory funnel with 2 or 3 portions of from 20 t o 40 cc. of bromine water. From 90 t o 95 per cent of the arsenic were found in the bromine water portion a t the first separation and, except with large amounts, two separations gave all the arsenic, together with the selenium which was present, and some sulfuric acid. The bromine water extracts were united, filtered and the excess of bromine removed by passing air through the solution. The arsenic was precipitated by t h e use of phosphate solution and magnesia mixture. T h e precipitate was collected on a filter, washed once with 2.5 per cent ammonia and dissolved. If the amount of arsenic was small i t was determined colorimetrically as in the case of hops. If a larger amount was present the precipitate was dissolved in 2 j cc. of dilute hydrochloric acid (sp. gr. 1.10) and the arsenic reduced b y heating for I O min., after the addition of I cc. of solution containing 0.5 g. stannous chloride and 2 cc. of solution containing 0.375 g. potassium iodide per cc. The selenium was largely precipitated a t this point, carrying with i t much of the arsenic. If the precipitate is not filtered out the arsenic is all recovered. More hydrochloric acid was added t o bring the total amount of concentrated acid u p t o 28 cc. The solution was washed into the generating bottle which had a capacity of about 140 cc., and the volume was made t o about 1 2 0 cc. Six pieces of zinc were now added and the gas passed into mercuric chloride solution, as described by Smith. Glass wool moistened with lead acetate solution served t o keep back hydrogen sulfide. The generator was cooled t o about 10' C. a t first, so t h a t the action would not be too violent. After z or 3 hrs. the mercuric chloride solution with the precipitate was boiled gently one-half hour. When cool, the precipitate of mercurous chloride was collected on ignited asbestos in a Gooch crucible, washed with alcohol and dried a t 110'. After weighing, the crucible was ignited t o drive off the mercurous chloride and weighed again t o give the weight of precipitate. The results by this method were as satisfactory as those given b y Smith in his description of the method. RESULTS
The sun-dried hops contained from 0.1 t o 0.2 part of arsenic (As2O8) per million, the sulfured hops from 0.2 t o 2 6 p. p. m., and the samples of sulfur gave from 3.6 t o 3 5 6 p. p. m. The relation of the different lots showed very clearly t h a t the contamination of the hops must have come from the arsenic in the sulfur. This naturally led t o consideration of t h e possibility of contamination of dried fruits which are treated with sulfur fumes. Samples of peaches a n d apricots collected a t a local store gave 0.2 t o 2 . 0 parts of arsenic per million parts. Samples of peaches which had been collected for another purpose contained from 0 . 7 t o 1
THISJOURNAL, 7 (1915), 849.
364
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
2 . 0 parts of arsenic per million. Samples of dried apples which were in storage gave from 0.1t o 0 . 5 part of arsenic per million. Mr. R. S. Hiltner, who was engaged in an investigation of the drying of fruit from other points of view, kindly furnished I O samples of sulfured peaches and apricots and samples of the sulfur used in treating them. The samples of dried fruits contained from 1.4 t o 3.4 parts of arsenic per million. The samples of sulfur contained from 5 t o 500 parts. The source of the samples of sulfur was not known. The samples of sulfur which were studied in connection with the occurrence of arsenic in hops were all Japanese sulfurs. I n connection with this subject, some samples of Japanese sulfur were collected a t the port of San Francisco and examined for arsenic. They contained from 5 5 t o 7 0 0 parts of arsenic per million. Through the kindness of Mr. Philip S. Smith, of the U. S. Geological Survey, samples of sulfur were obtained from six of the companies producing sulfur in the United States. I t is generally recognized t h a t sulfur obtained from the largest source of supply in the United States is free from arsenic. The sample from this source, and all the other samples examined, showed no arsenic, or less than one part of arsenic per million. Thus i t appears t h a t food products which are treated with sulfur fumes from sulfur which contains arsenic are liable t o contamination with arsenic. I n the case of hops the use of sulfur containing a n amount of arsenic of about I O O p. p. m. will, on the average, introduce about three parts of arsenic per million parts of dried hops. It appears probable t h a t if sulfur. which contained less t h a n ten parts of arsenic per million were used for sulfuring hops or dried fruits, it would be almost impossible t o detect any contamination of the sulfured products with arsenic. I t also appears t h a t the native supplies of sulfur in this country are free from arsenic and if used for sulfuring food products would make it certain t h a t no contamination with arsenic could. result from the sulfur. The amount of sulfur burned for curing food products is a comparatively small proportion of the total amount used. The greater part, which is used in making lime-sulfur mixture for spraying and dipping and as powdered sulfur for dusting vines of different kinds, would, of course, introduce no appreciable contamination of arsenic into the food products, even if the sulfur did contain large amounts.
FOODINVESTIOATION LABORATORY BUREAU OB CREMISTRY, u. s. DEPARTMENT OF AGRICULTURE WASHINGTON, D. C.
SOME CONSTITUENTS OF THE AMERICAN GRAF’EFRUIT (CITRUS DECUMANA)’ By HARPERF. ZOLLER Received January 14, 1918 INTRODUCTION
The adoption of the grapefruit in America as a valuable food accessory has spread with amazing 1 Abstracted before the Spring Meeting, American Chemical Society, Kansas City, Mo., April 1917. The major portion of the work was carried on in the chemical laboratories, Kansas State Agricultural College, Manhattan, Kansas.
Vol.
IO,
No. 5
rapidity, so t h a t now it is possible t o obtain this fruit in season in practically every remote village in the United States or Southern Canada. This wholesale distribution has necessitated an industry which bids t o become of greater vastness t h a n either the lemon or orange industries, if proper market conditions and disposal of wastes can be secured. The fact t h a t a successful season in the citrus industry depends upon favorable weather conditions and orchards free from certain pathological plagues, indicates t h a t citrus by-products are sure t o become a n important factor. I n the sorting and grading of the thousands of tons of grapefruit, representing a season’s crop, many tons of culls are allowed t o rot for the want of an economical disposal. Certain of the producing companies are seriously contemplating the isolation of certain of t h e by-products, and one or two companies have engaged in extractions on a minor scale. I a m of the opinion t h a t with a proper knowledge of the important constituents their commercial production would become profitable and the trades would be supplied with the raw materials which they demand. I t seems probable t h a t extended analysis of the grapefruit must have been made by chemists in the employ of the citrus fruit companies, but if these have been made they have not been published a t large. It is my purpose in this paper t o present some research data on the nature and quantities of certain of the more important constituents of the American-grown grapefruit from different sources, with the idea t h a t it should prove valuable t o those intimately connected with t h e citrus orchards in the South and West. HISTORICAL AND COMMERCIAL ASPECTS
Before proceeding with the data it would be well t o consider briefly the historical and botanical significance of the grapefruit. Textbooks on botany, scientific journals and current publications are remarkably free from allusions t o this fruit.‘ Hume says, “ N O fruit of importance now grown in the United States has such a meagre American literature as the pomelo. Nor is this strange when we remember the fact t h a t i t is only within the last fifteen years or so t h a t the pomelo has been regarded as a commercial fruit.”’ * But i t is strange t h a t since Hume’s edition of his bulletin in 1901 much less literature has ap1 In searching through the Library of Congress for early literature on the citrus fruits, with the hope of gaining an insight into the past history of grapefruit, I was fortunate enough t o find Giovanni Batiste Ferrari’s book on the “Hesperides” published in Rome in 1646. This work, consisting of over 800 pages, and replete with full-page woodcuts of t h e various species of citrus, proved t o be the most complete record of the citrus fruits of the Orient to date. It is not surprising t h a t we find herein described the varieties of the different species from many of the islands of the Pacific (including Java), Egypt, Greece, India and Italy. While Ferrari classifies the species similar to the grapefruit under Aurantium, it is not unlikely t h a t one of the following most closely resembles the grapefruit as we know it: Auvantium Dulci Cortice el Sinense, p. 430; Aurantium Pomum, or Pomum Adam, p. 309; Aurantium Maximum, p. 437. It is difficult, from the description and woodcuts, t o say definitely just which one most closely resembles our typical American fruit. Perhaps the three are not distinct species, one or more may be hybrid varieties. It is clear t h a t Auranlium Dulci Cortice and Awantium Pomum (Adam’s Apple) are variously considered as the “forbidden fruit” of the early Orientals: a t least so considered by Ferrari, Johannes Commelin (Nederlantze Hesperides, 1676) and Gallesio (Lac. cit.); and most reasonably, because of their extreme bitterness. Numbers refer t o References in Bibliography, p. 373.
*
