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Plant physiologists and others interested in the periodic accumulation and depletion of the reserve carbohydrates in plants have long recognized the need for a rapid method for the estimation of the readily available carbohydrate fraction. This is especially true in applied studies such as those concerned with the efficient management of pasturage or forage plants. Undoubtedly, many worth while projects of an applied nature have never been undertaken because of the lack of time to carry out the tedious fractionation of the individual carbohydrate constituents.H. WEINMANN (9) has recently published a method for the determination of the total available carbohydrates in plant material by a single determination. The present paper reports a summary of the studies on the analytical aspects of the method as well as its applicability to the study of the seasonal trends in the carbohydrate reserves in the storage orgalls of switch cane (Arundinara tecta), a plant readily grazed by eattle. MethodsThe samples were taken at monthly intervals, or oftener, from a restricted portion of a uniform stand of switch cane in the Hofmann Forest in eastern North Carolina. The cane averaged about four feet in height.Small blocks of sod were dug with stems intact and washed free of soil. Roots were removed and discarded. Rhizomes (including the underground portion of the stems), aerial stems, and leaves were divided into separate samples: 250 grams each of stems and rhizomes and 150 grams of leaves.To facilitate drying, stems and rhizomes were cut into short segments an inch or less in length. Leaves were collected only during the months when there was a reasonably abundant supply (June through December).There was some variation in the drying procedure due to the equipment available. The first five samples (April through June, 1947) were held in an oven at 1000 C. for approximately onie hour and then dried to constant weight at 70°to 750 C. without forced draft. The remainder of the samples were dried under forced draft at 70°C. The collections were made at a point more than 100 miles from the laboratory and, therefore, several hours (usually 6 to 18) elapsed before the samples were placed in the drying oven. After the samples were dried, they were shipped to the

In the preceding paper (1) it was shown that 1,3,5-hexatriene might serve as the basis of a general synthetic method for condensed ring compounds of angular construction, such as steroids, since it was possible to secure, as the principal product of its addition to a cyclohexene, a derivative of 1-vinyloctahydronaphthalene with the annular double bond probably in the 2,3-position. The utility of this intermediate in the synthesis of angular polycyclic compounds would depend on its ability to isomerize to a 1-vinyl-l-octalin which could then add a dienophile. Before the feasibility of this procedure could be tested, we had observed that a 1,5-diene-3-yne can add two molecules of dienophile to give a crystalline product and it has now been found that this addition proceeds in the manner required for the synthesis of compounds of the type sought. In 1933 Blomquist and Marvel (2) found that both 4,7-di-n-propyl-3,7-decadiene-5-yne and 6,9-dimethyl-5,9-tetradecadiene-7-yne added two moles of maleic anhydride in boiling xylene. Since the products of reaction did not crystallize, the solution in xylene was heated with aqueous alkali. Neutralization of the alkaline extract gave products with the composition RéCuHioOs but, as these were amorphous, no attempt was made to characterize them further.We have now heated 2,5-dimethyl-l, 5-hexadiene-3-yne (I) with maleic anhydride at 130°. From the reaction-mixture a crystalline product, CieHuOe, was isolated. If the two moles of maleic anhydride added one after the other in the manner of a Diels-Alder reaction, then III and IV would be the expected structures.2 The intermediate II has not been

Two groups of beef cattle, consisting of two steers and one cow per group, received a total dose of 300 mg. of p,p'-DDT per kg. of body weight over either a 3or 30-day period. One steer from each group was sacrificed before a 7-week depletion period which followed the treatments. The remaining animals were sacrificed at the end of 7 weeks of de-pletion. Total DDT residues (DDT, DDD, and DDE) appeared on the average to be evenly dis-tributed throughout the extractable fat of beef cattle, based on samples of 13 different tissues. Differences were found in the total DDT residue content of extractable fat due to dose rate (P < 0.01) and time after treatment (P < 0.01), and the relative amounts of DDT, DDD, and DDE were different (P < 0.05) between depot fat, muscle, blood, and milk fat.

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