ISSN:0022-5142    

DOI:10.1002/jsfa.2740010902

出版商:John Wiley&Sons, Ltd    

年代:1950

数据来源: WILEY

摘要:

AbstractThe presence of arsenic in materials dried over coke fires is quite well known. It is shown that chicory dried in England is no exception to this and that arsenic is transferred from the coke to the chicory. Most of the arsenic appears to be present on dried chicory in the form of dust but it cannot be said definitely that this dust is entirely flue dust. Both the volatile and nonvolatile arsenic contents of coke must be taken into consideration. The fate of the arsenic on the dried chicory during subsequent processing has been investigated. It is concluded that the arsenical contamination of dried chicory does not present any considerable risk to the consumer of chicory.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740010903

出版商:John Wiley&Sons, Ltd    

年代:1950

数据来源: WILEY

摘要:

AbstractThe standard phenoldisulphonic acid method of Chamot and Pratt is modified, the nitration being carried out in aqueous solution. A photoelectric method of measuring the colour intensity is employed. The modified method is very rapid in use and has a greatly reduced susceptibility to interference by chlorides or by precipitation of metallic hydroxides and phosphates. The effect of variations in technique is examined and a study made of the level at which interference takes place with the more commonly occurring ions. The general applicability of the method is discussed.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740010904

出版商:John Wiley&Sons, Ltd    

年代:1950

数据来源: WILEY

摘要:

AbstractPresent economic trends suggest that hog‐ and cattle‐pancreas as a source of tryptic enzymes for the manufacture of leather bates may become scarce in the future. An investigation has therefore been conducted on the waste visceral residues' from certain suitable fish obtainable in South African waters (snoek, kingklip and stockfish) with the object of developing a cheap alternative source of bating enzymes. The preparation of a wood‐meal enzyme from the gut of such fish is described and shown to be practicable.A new technique is described for assessing the relative bating power of commercial and experimental bates, based on changes in thickness and weight of the pelt pieces and practical assessment of the bated pelt. The use of statistical methods of experimental design permits of comparison between the experimental preparations and a typical commercial bating material as well as a control treatment involving no enzyme. It has been shown that under practical bating conditions there is no difference in bating action between the experimental material and the commercial sample when the initial concentrations are adjusted to give equivalent gelatin‐liquefying potency and the same relative proportion of ammonium salts is

ISSN:0022-5142    

DOI:10.1002/jsfa.2740010905

出版商:John Wiley&Sons, Ltd    

年代:1950

数据来源: WILEY

摘要:

AbstractThe effectiveness of nine species of Chinese insecticidal plants have been tested against 40 species of insects. The toxicity of three species, namely,Millettia pachycarpaBenth.,Tripterygium ForrestiiLoes. andRhododendron molleG. Don were studied in detail. The rotenone‐bearing plants,Millettia pachycarpa, Pachyrrhizus erosusUrban andDerris FordiiOliv., are stomach‐ as well as contact‐insecticides. The finely ground seeds ofMillettia pachycarpa, when applied as sprays in suspension, were highly effective against aphides, Pentatomids and leaf‐beetles. The root bark of the wrinkle‐fruited thunder‐god‐vine,Tripterygium Forrestii, contains an alkaloid and other unknown toxic principles. Data obtained from laboratory and field tests show that the root bark of this plant acts as a powerful repellant and as a stomach‐insecticide. When applied as dusts it was found to be effective in protecting vegetables from the attack of leaf‐beetles and certain species of lepidopterous larvae. The toxicity of the root bark of the bitter tree,Celastrus angulataMaxim., is similar to that ofTripterygiumbut it appeared to act also as a contact‐poison. The root ofStemona tuberosaLour. is a contact‐poison, and alcohol extracts were effective against the body lice and plant lice. The stems and rhizomes of the black hellebore,Veratrum nigrumL., is a stomach‐ and a contact‐poison : it is used by the farmers for house‐fly control. The flower ofRhododendron mollewas found to be a contact‐ and stomach‐poison. Its toxicity is very specific, being effective only against certain species of lepidopterous larvae, Pentatomids and leaf‐beetles. The rootstock ofSteller a chaemejasmeL. contains an active antibiotic principle which acts also as a repellant and as a contact‐poison against tent caterpillars.The toxicities of insecticides of vegetable origin were compared with modern synthetic insecticides under laboratory conditions. As a contact spray against the cruciferous leaf‐beetle,Colaphellus bowringiBaly, γ‐benzene hexachloride appeared to be more toxic than rotenone but rotenone was about four times more toxic than technical DDT and its killing action was much quicker than that of γ‐benzene hexachloride and DDT. γ‐Benzene hexachloride was 306 times more toxic than the seeds ofMillettia pachycarpa. Based on the time‐mortality curves, however, a 5% water suspension of the seeds ofMillettia pachycarpacompared favourably with a o.1 % γ‐benzene hexachloride spray when used against the ten‐spotted grape leaf‐beetle,Oides decempunclataBillberg. As a stomach‐poison against the fifth‐instar Small White butterfly,Pieris rapaeL.,Millettiaseeds proved to be more toxic than phenothiazine.Apart from the standard botanical insecticides such as derris, pyrethrum and nicotine,Millettia pachycarpa, Pachyrrhizus erosus, Tripterygium Forrestii, Celastrus angulata, Rhododendron molleandVeralrum nigrumare widely distributed in China and have great possibilities for extensive cultivation as an easily available source of cheap insecticide. These insecticidal plants have no phytotoxic effect and with the exception ofRhododendronandVeratrumthey are not very toxic to human beings. The danger of chronic poisoning from the daily consumption of foodstuff treated with these insecticides seems remote. Recommendations are made for further investigations of these plants with special emphas

ISSN:0022-5142    

DOI:10.1002/jsfa.2740010906

出版商:John Wiley&Sons, Ltd    

年代:1950

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740010901

出版商:John Wiley&Sons, Ltd    

年代:1950

数据来源: WILEY