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essential thermo-chemical data. We have not, a t this time, found a mechanical or chemical method of isolating the undecomposed Cyanamid particles from a complete fertilizer mixture, other t h a n b y hand-picking, which a t best affords a partial separation of the coarser particles. A s a concrete example of the proof of such undecomposed Cyanamid present in a fertilizer mixture might be cited t h e case of a ten-ton batch made up as indicated below: FORMULA 1000 acid phosphate 125 granulated Cyanamid 200 muriate of potash 300 garbage tankage 375 filler
PER CENT P20r I N ACIDPHOSPHATE GARBAGE TANKAGE Free a c i d . . . . . . . . . 3 . 6 4 .... Water-soluble.. . . . 12.64 0.15 Citrate-soluble.. , . . 4 . 5 3 2.55 Available. . . . . . . . . 1 7 . 1 7 2.io Insoluble.. . . . . . . . 0 . 2 9 1.19 Total. , , . , . , . . 1 7 , 4 6 3.89
This batch was stored in a bin, surrounded on all sides b y similar bins containing similar mixtures, and t h e center of the mass rose 70' C. in four days after mixing, and then slowly cooled off. Six weeks after mixing, a sample was drawn while still warm t o the hand, from which sample we picked out sufficient undecomposed Cyanamid for analysis. This Cyanamid was clean and free from adhering acid phosphate, which realiy seeme'd t o have as great a n affinity for t h e garbage tankage as for t h e Cyanamid. T h e separation in this manner offered difficulty only because of t h e presence of the dark-colored particles of t h e tankage and t h e dark colored filler used, and not because o f . adherence of t h e acid phosphate. An analysis made directly on the particles, as separated without attempting t o clean t h e m off in any way, gave 48.5 per cent calcium hydrate and 0.1.5per cent phosphoric acid, showing the presence of the hydrate in t h e particles as sampled. The granules of Cyanamid showed decomposition of t h e cyanamide and the presence of moisture, which probably is the cause of t h e lessened percentage of hydrate found in them. We have endeavored t o show here t h a t t h e Official Methods of Analysis give results in no way indicative of t h e character of the sample as taken where free calcium hydrate or Cyanamid is present in the mixture. Such results show an apparent loss of availability t h a t has no real significance as far as concerns t h e condition of t h e material before analysis. Granulated Cyanamid remains for a large part unacted upon even in additions as high as 300 Cyanamid t o 1000 acid phosphate and a t temperatures as high a s 110' C. It is more decomposed in t h e manipulation incident t o analysis b y the official methods t h a n in the mixing with t h e acid phosphate, if we can believe t h e results of some recent investigations we have made. We regret t h a t we cannot offer a solution t o this problem, which not only concerns t h e Cyanamid industry, b u t t h e larger fertilizer industry as a whole who have been striving t o use limestone fillers in their mixtures for the great beneficial effects following the use of such fillers. The use of such material is now prohibited because of the great loss of availability shown on analysis b y the Official Methods. We believe t h a t i t is impossible for calcium carbonate, as well as t h e hydrate we have worked with, t o transform
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a n acid phosphate past the dicalcium stage under the ordinary conditions of mixing and batching of t h e semi-dry materials employed to-day. B u t we do know t h a t t h e digestion with neutral citrate will cause reaction of any free hydrate with the di-calcium phosphate a t t h a t stage of t h e manipulation, and t h e same must be true of t h e carbonate, though we have not made a direct investigation t o prove this statement. I n our own work we have found t h a t t h e dilute weak acids frequently recommended for analysis of t h e Basic Slags show practically no loss of available in acidphosphate mixtures containing u p t o 300 pounds of granulated Cyanamid and 1000 pounds of acid phosphate t o the t o n of complete mixture, even though t h e temperature of t h e mass rose t o over 110' C. and remained high for many weeks. Such methods do show a loss of available for additions of powdered Cyanamid much in excess of 125-150 pounds t o the 1000 of acid phosphate, though this amount has, in many cases, been exceeded by a proper choice of inactive diluents in t h e complete mixture. The results of analysis of Cyanamid acid phosphate mixtures b y these last-named methods agree more closely with other physical and thermochemical data t h a n do those obtained b y the Official Methods. We believe t h e great importance of a comprehensive study of t h e reactions between acid phosphate and calcium hydrate and calcium carbonate under t h e mixing conditions existing in actual fertilizer practice would lead towards a solution of t h e use of a limestone filler for fertilizer mixtures, and everyone appreciates t h e great agricultural advantage t o be derived from t h e use of such a material in t h e industry. The problem should be approached from several angles, not all purely chemical, as we have shown t h e failure of a chemical method t o produce results characteristic of the material worked upon in our case as described above. NIACARA FALLSONTARIO
A STUDY OF THE MILK OF PORT0 RICAN C O W S By HOWARD J. LUCAS,R . DBL VALLB SARRAGA AND J. ROMAN BENITEZ
Received September 15, 1913
This work was undertaken for the purpose of .determining how, and t o what extent, the milk from the native Porto Rican cows varies from t h a t of other countries. and to what extent t h e use of different grasses as food affects its composition. The so-called native cow does not seem t o be of any particular breed, b u t appears t o be t h e result of the mixing of different strains introduced into t h e island from time t o time. There seems t o be no attempt on the part of the people t o divide t h e cattle into different breeds on t h e basis of color, and consequently no attempt has been made t o do so in this work. The value of cattle in Porto Rico does not depend entirely upon its use as a source for meat and for milk, but rather upon the fact t h a t the oxen form t h e most common beast of burden, and are used in all parts of the country for performing the heaviest kinds of work, such as hauling, plowing, rough farm labor, etc.
J a n . , 1914
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
It is only natural t o suppose, then, t h a t t h e utility of t h e cow as a milk producer has been lost sight of t o a greater or less extent, and emphasis has been placed upon t h e desirability of raising oxen for agricultural purposes. Therefore, i t is reasonable t o conclude t h a t but little attention has been given t o t h e improvement of t h e stock for milk production by suitable methods of breeding. The peculiar manner of milking is undoubtedly an unfavorable factor in milk production. This is done but once tin every twenty-four hours, and then under conditions which must always be complied with. The COWS have been so bred and so accustomed to thismethod of procedure t h a t they refuse t o let down milk otherwise. The calf is first allowed t o s t a r t the flow of milk and is then removed, t h e milk-man continuing t h e operation until he has obtained all t h a t he possibly can. The calf is again allowed t o suckle, and i t is often possible t o obtain a second milking by again removing it, although it is not customary to do so in t h e large dairies. All this involves a great waste of milk, and a loss of labor and time necessary for handling and herding t h e calves during t h e milking process. Such an unscientific method has a decided influence upon t h e € a t content, which might vary considerably, depending upon whether much or little of t h e strippings are secured. As b u t little grain is fed, t h e cows are kept in t h e pastures t h e year round. Certain sections of t h e island, notably t h e southern half, receive rain for a part of t h e year only, and during t h e remainder suffer from drought. During these periods t h e pastures dry up, and t h e cattle suffer from lack of food. This condition naturally leads t o decreased production of milk, and this factor, together with t h e peculiar custom of milking, and the deterioration of t h e strain through lack of proper breeding, has brought t h e native cow of Porto Rico t o a state of low efficiency as a milk producer. Daily yields run from 1-10 or 1 2 qts. and 5 is considered a good average. This condition can not be attributed t o t h e prevalence of disease; on the contrary, i t is a well known fact t h a t the cattle of the island are remarkably frcc from tuberculosis, and have strong resisting powers against those diseases t o which they are liable. With the exception of work done b y R . del Valle Skrsaga (office 3f Health, Charities and Correction, Chem. Laboratory, Bul. No. 2 ) on samples of milk from two cows a t stated intervals, there have been no published analyses of milks of known purity f r o m cows on t h e island. I t was hoped t h a t this work might prove t o be a guide for establishing a standard €or Porto Rico. C O L L E C T I O N O F sAMPLEs--At first i t was t h e intention of t h e authors to collect t h e samples personally, b u t later as it became desirable t o obtain t h e m Erom all parts of t h e island, t h e Director of t h e Laboratory issued a circular requesting t h e health officer of each municipality t o forward two samples of milk of known purity t o the laboratory. They were directed t o personally supervise t h e milking of two cows, takir.g care t o have t h e milking complete, and t h e whole
23
thoroughly mixed before withdrawing t h e sample, consisting of 250 cc. T o t h e latter was t o be added five drops of a 40 per cent formalin solution before sending t o t h e laboratory. The following data in regard t o each sample were requested : (1) (2) (3) (4)
Quantity of milk given b y t h e cow. Age of cow. Time calved. Kind of grass used as food.
It was further requested t h a t , if possible, one cow should be six months or more calved, and t h e other two months or less. Due t o a misunderstanding, many officials sent wrong data for t h e quality of milk. I t follows from t h e above t h a t the value of this work depends upon t h e reliability of t h e men who collected t h e samples, and i t is felt t h a t they have accomplished their work in a conscientious manner. The samples were collected from December t o May, t h e majority during February A N A L Y S I S O F SAMPLES-The specific gravity was taken with a Quevenne lactometer, which had been standardized against t h e Westphal balance. Proper corrections were made for t h e temperature when other t h a n 1j.6" C. The f a t was determined according t o the method of Babcock. Total solids were determined b y evaporating five grams of milk t o dryness in a platinum dish on the water b a t h , and heating for four hours a t 100' C. in the water oven. Previous experiment had shown t h a t constant weight was obtained a t t h e end of this time, but t h e results may be low, as t h e residue was often more or less brown. On a number of samples total solids were not determined b y drying, because a t one time the milks came in so rapidly t h a t facilities for so doing were lacking. T h e dry residue was burned off in t h e muffle furnace a t a low red heat and weighed as ash. Solids were calculated on all samples by t h e use of the Richmond slide rule. Lactose was determined polariscopically, using acid nitrate of mercury as t h e clarifying agent.' The refraction of t h e copper serum was taken according t o the method of Lythgoe.2 INTERPRETATION O F RESULTS
Table I gives the results of analyses, tabulated according t o f3t content. of some typical milks, selected from a list of 140 analyses, which lack of space prevents giving in its entirety. Solids-not-fat are calculated from solids b y drying when given, otherwise from solids b y calculation. Table I1 gives t h e maximum, minimum and average of each determination. Under total solids are included solids by drying, and of such t h e solids by calculation were used for calculating solids-not-fat. The percentage of fat is seen t o vary within exceedingly wide limits, from 0.8 per cent t o 10.2per cent; total solids also have a wide range. The maximum for solid+not-fat, ash, lactose, and refraction of copper serum are exceptionally high, showing t h a t certain of the milks could be heavily watered without being detected by chemical means. 1 1
U. S. 1)ept. of Agr., Bureau of Chemistry, Bul. 107 (rev.), 118 U. S. Dept. of Agr., Bureau of Chemistry. Bul. l S 2 , 124.
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Vol. 6, No.
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TABLE I-TYPICALMILKS (FAT-LACTOSEIN PERCENTAGES) Time Age of since cow calving Yrs Mo.
Date 4-1 5-1 3 3-29-13 2-18-13 2- 6-13 2-1&13 4-16-13 2- 7-13 4-23-13 2-11-13 1-20-13 5-21-13 5- 15-1 3 4-30-13 5-14-13 2(-17-13 1-20-13 5-23-13 5-23-13 4-21-13 2-24-13 4-3C-13 4-18-13 4-21-13
4 4 5 6 7 5 8 4 5 10 5 3.5 3 4 7 9 5 4 3 4 5 8 7
Volume of milk Qts.
Kind of food
6 9 2 6 6 2 6 6 2 6 7 1.5 5.5 6 6.5 1 6 1.5 2 2 1.5 7 8
G.(a)
..
Gr.-M. G. M. P. P. P. M.-G. G. M. P. M. M. Ma. G. M. M. GI. P. P. M. G.
.. 3 7
., 7 2 , '
P.
.
4 10
.
,
.. 4 3 7 7 5 7
.. ..
7
..
..
Specific gravity (15.6' C.) 1.0330 1.0337 1.0285 1.0313 1,0318 1.0340 1,0305 1,0323 1.0370 1.0348 1,0380 1.0302 1.0350 1.0342 1.0330 1.0370 1.0347 1.0315 1.0342 1.0330 1,0376 1.0353 1.0346
(a) G. = yerba de guinea (guinea grass).
Fat
Total solids b y calculation
Total solids by drying
10.2 8.6 8.0 6.8 6.6 6.3 5.8 5.4 5.0 4.4 4.1 4.0 3.9 3.7 3.4 3.0 3.0 2.9 2.6 2.1 1.6 1.0 0.8
20.6 18.9 16.9 16.1 16.0 16.2 14.75 14.7 15.4 14.15 14.55 12.5 13.6 13.15 12.5 13.0 12.4 11.5 11.8 11.0 11.55 10.2 9.75
20.66 19.04 17.00 16.17
M . = malojillo.
Table 111 gives t h e analyses of those milks which showed abnormally low results in one or more deterTABLE I1 SolidsTotal notsolids Water f a t
Sp. gr. 16.6O C. F a t
Maximum . . . . . . 1.0386 1 0 . 2 20.66 9 0 . 6 0 10.75 Minimum . . . . . . 1.0285 0 . 8 9.40 79.34 8.27 Average . . . . . . . . 1,0337 4.22 1 3 . 6 3 86.37 9 . 4 2
Refraction copper Ash Lactose serum 0.86 0.63 0.74
5.67 4.00 4.99
40.0 36.0 38.28
minations other t h a n fat and total solids. Although Nos. I , 2 , and 3 have all t h e appearance of being wa-
... 16.58 I
.
.
15.36
...
14.04 14.85 12.64 13.43 13.24 12.34 12.68 12.27 11.17 11.78 10.82 11.36 9.98 9.40
P. = pasto c o m h .
Water
Solidsnotfat
79.34 80.96 83.00 83.83 84.0 83.42 85.25 84.64 84.6 85.96 85.15 87.36 86.57 86.76 87.66 87.32 87.73 88.83 88.22 89.18 88.64 90.02 90.60
10.46 10.44 9.00 9.37 9.4 10.28 8.95 9.96 10.4 9.64 10.75 8.64 9.53 9.54 8.94 9.68 9.27 8.27 9.18 8.72 9.76 8.98 8.60
Gr. = grama.
Ash 0.80 0.85 0.66 0.74
.. 0.73
..
0.75
..
0.77 0.84 0.63 0.75 0.63 0.76 0.76 0.71
..
0.73 0.68 0.77 0.79 0.78
Refraction copper serum 200 c. Lactose 5.01 4.00 4.82 4.79 4.57 4.94 4.85 4.52 5.09 5.30 5.07 4.77 4.92 5.43 4.61 5.67 4.75 4.75 5.02 4 81 5.26 4.29 4.37
39.4 38.5 38.1 37.9 38.3 39.6 37.8 36.8 39.2 39.0 38.8 36.9 38.5 38.5 37.4 40.0 37.9 37.6 37.4 37.3 38.9 36.5 36.9
M a . = matojo.
also grama and matojo; pasto comGn may be a mixture of any of these, and is used t o designate a n y ordinary pasture containing different varieties of grasses. The average for cows fed upon guinea grass is much higher t h a n for those fed upon t h e others. Those milks from cows fed upon more t h a n one kind of pasture are not included in this table. SUMMARY-This work is t h e first of a series of analyses t o be made for t h e purpose of determining a standard for Porto Rican milk.
TABLE111-ABNORMAL MILKS
Date 4-23-13 5-20-13 5-20-13 5- 13-1 3 5-1 4- 13
Time since calving Mo.
Age Yrs. 4 4 6 4.5 12
.
4.5 4.5 11.0 3.5 6
Kind of food
T.'olume of milk Qts.
.
P. P. P.
4 2
P. G.
2
,
Specific gravity (15.6' C.)
Fat
1.0249 1.028 1,023 1.0301 1.0288
4.2 2.6 5.3 3.1 3.2
tered, investigation has shown t h a t they are genuine milks, and duplicate samples, taken by special inspector, gave similar results. If the standard for milk in Porto Rico were made t o include milks which give results as low as those in Table 111, i t would allow watered milk t o be sold extensively. Further work TABLEIV-EFFECT
OF
FOODUPON FATCONTRNT Per cent
.
K i n d of food Maximum Minimum Average Guinea grass.. . . . . . . . . . . . . . 1 0 . 2 1.0 4.71 Malojillo.. . . . . . . . . . . . . . . . . 7 . 8 1.3 3.98 Matojo . . . . . . . . . . . . . . . . . . . 3.7 3.7 3.7 Pasto cornfin.. . . . . . . . . . . . . . 7 . 0 0.8 3.37 Grama., . . . . . . . . . . . . . . . . . . 3.8 2.9 3.35
No. of samples .22 44 1 53 2
is necessary in order t o determine the prevalence of those milks with abnormally low constants. Table IV shows t h e effect of feed upon f a t content. Guinea grass (yerba de guinea), malojillo, and pasto comfin are t h e pastures most in use. Guinea grass and malojillo are separate and distinct grasses, as are
Total solids b y calculation 11.4 10.3 12.25 11.4 11.15
Total solids by drying 11.45 10.22 12.71 11.28 10.82
Water
Solidsnotfat
Ash
88.55 89.78 87.29 88.72 89.18
7.25 7.62 7.41 8.18 7.62
0.55 0.59 0.51 0.63 0.69
Refraction copper serum Lactose (20° C.) 3.64 33.4 4.14 34.2 3.51 32.6 4.22 35.2 4.11 37.6
The native Porto Rican cow is milked but once daily, and gives a small yield of milk. Factors which conduce t o this are: ( I ) Deterioration of strain through inattention t o proper breeding; ( 2 ) improper milking methods; (3) insufficient food during certain seasons. The cattle are remarkably free from tuberculosis. The milk may vary within wide limits as regards total solids and fat content, and may run exceptionally high as regards solids-not-fat, ash, lactose, and refraction of copper serum. Certain milks ran exceptionally low in one or more determinations, and these were discarded from the standard until further work could be done. Guinea grass seems t o be t h e best adapted as a pasture for cows, t h e f a t content averaging considerably higher in t h e milks from cows so fed. Further work should be done, particularly with milks taken during t h e summer months. CHEMICAL
AND
BROMATOLOGICAL LABORATORY
SAN'JUAN, PORTO RICO
