A New Method for the Qualitative Detection of Casein in Woods T. H. WHITEHEAD, University of Georgia, Athens, Ga.
T
HE process of treating woods with casein solutions is becoming very useful to such specialized industries as baseball bat, handle, and related manufacture. The usual method is to treat the wood with a solution of ammonium caseinate, ammonia, and lime with sufficient air pressure applied to increase penetration of the casein solution into the wood. Then a second treatment with either formaldehyde vapor or formaldehyde solution renders the casein insoluble in water (2). The objects of this treatment are to prevent splitting of the wood on its surface and to render the surface waterproof, so that swelling will be prevented or greatly reduced. However, the treatment tends to reduce resiliency, it is important in the manufacture of these products to retain as much of the original resiliency of the wood as possible. Obviously then, it is valuable to be able to control the depth to which the casein solution penetrates, in order to obtain the optimum conditions for each wood, This can be done if this depth can be determined.
QUANTITATIVE CONFIRMATION Two disks of ash wood were stained as above to get indications of regions in which casein was present. The staining was identical in both sections. Three more disks were then cut from the same cylinder as the first two and divided into sections indicated by the stain. The first sections were taken from the outermost rim into the wood for 0.5 inch; the second sections from here into the wood for another 0.5 inch; the third sections were the remaining cores. Each section was analyzed for its nitrogen content according to the Kjeldahl method (1). Similar analyses were made on untreated wood to be used as blanks. The untreated wood sections showed an average nitrogen content of 0.03 per cent with very little variation. This was subtracted from determinations made on treated sections and the difference multiplied by 6.25 to convert nitrogen t o casein. The results showed clearly that the stain was reliable: ,
REQION
Mix a solution containing 4 grams of hematoxylin In 25 ml. of 95 per cent alcohol with 400 ml. of a saturated aqueoue solution of ammonium alum. dfter standing in the a1r for 4 days, add 100 ml. of glycerol and 100 ml. of methanol. Cork well. 1
CABEINFOUND
%
EXPERIMENTAL The material used in these tests was obtained by cutting cross sections from the woods (ash, yellow poplar, and hickory) about 0.25 inch thick. This gave small disks, as the original samples were cylinders. The wood in each case had been thoroughly seasoned. Neither the standard chemical tests nor several biological stains for casein worked on the casein-formaldehyde compound. However, a satisfactory method was obtained using Delafield’s solution of hematoxylin.’ It was found that simply dipping sections in this stain, washing, and drying did not produce as clear-cut results as the following method: Soak the section of wood to be tested in distilled water for at least 15 minutes. Remove and shake off excess water. Dip the section into Delafield’ssolution of hematoxylin so that all the wood is covered for 2 minutes. Remove section and allow the excess stain to drain off into the solution. Rinse well with running water until all adhering stain is washed off. Let it dry in the air. A violet stain will be imparted to regions of the woods in which casein is present, but no such stain is found in either untreated woods or portions of treated woods into which the casein solution did not penetrate. The tint of the stain roughly indicates the amount of casein present.
STAININQ
Outer Middle Inner
Intense Faint None
2 . 7 -2.9 0.67-0.59 None
DISCUSSION Since it has been stated (3) that all calcium salts are stained by nuclear stains in microscopic work, it was necessary to eliminate this factor. Sections which had been treated with lime water only did not become stained by the method given in this paper; in a macro method of this kind calcium salts do not interfere. It is believed that this method is applicable to the needs of other manufacturers of wood products. No elaborate technic or special apparatus is required, and the tests furnish a visible and permanent record which the plant manager can turn over to his executive for consideration. ACKNOWLEDGMENT The author gratefully acknowledges the help given by Julian Miller, Botany Department, University of Georgia. LITERATURECITED (1) Griffing, R. C., “Technical Methods of Analysis,” 2nd ed., p. (2)
478, McGraw-Hill, 1927. Martin, G., “Industrial and Manufacturing Chemistry,” Part 1,
(3)
Stengel, A. A,, “Text Book of Pathology,” 4th ed.,
6th ed., p. 527, Crosby Lockwood, London, 1922.
p. 871,
Saunders, Philadelphia, 1903. RECEIVEDNovember 5, 1932.
I
TOILETPREPARATION PRODUCTION IN RUMANIA.Rumanian roduction of toilet requisites, which is reported to be benefiting From the present tariff, amounted in 1931 to almost $1,000,000. Imports in the same year, shipped chiefly by France and Germany, totaled $250,000. Since exports of perfumes and cosmetics are negligible, Rumania’s entire consumption of toilet reparations exceeded $1,200,000. Progress has been made Ekewise in the local manufacture of toilet soaps, but separate production figures on these soaps, as distinct from ordinary types, are not available. Total soap production in 1931 was $1,920,000 and imports, $113,000.
Many of the leading foreign manufacturers both of toilet preparations and soaps have made arrangements t o manufacture their products locally, not alone because of duties but because raw materials are cheap and readily available. Since the population prefers products bearing foreign trade-marks, certain local producers have attempted t o meet this requirement by purchasing manufacturing rights for foreign brands on a royalty basis. A t present 90 per cent of the soap sold on the Rumanian market under foreign trade names is produced locally. The same applies to the majority of toilet preparations, including t,ooth pastes, mouth washes, powders, etc. 150
