摘要:

not available

ISSN:1923-4287    

DOI:10.1139/cjr29-001

出版商:NRC Research Press    

年代:1929

数据来源: NRC

摘要:

A program of investigations is outlined and the results of the first three years' work reported. Eight wheat varieties, differing widely in resistance to stem rust, showed no corresponding differences in the physico-chemical properties of their expressed tissue-fluids. The infection of susceptible varieties was in some cases reduced by administering extracts of resistant varieties in petri-dish cultures or by direct injection into inoculated leaves. The injection of the juice of infected leaves into healthy leaves failed to demonstrate the presence of any toxin excreted by the fungus. The injection of salicylic acid, catechol or vanillin in suitable concentrations frequently caused a reduction in infection. These phenolic compounds in very low concentrations stimulated the growth ofHelminthosporium sativum, but at higher concentrations inhibited it. The same phenols inhibited the germination of rust spores. On filtered wheat-juice rust spores also failed to germinate, though on unfiltered juice they germinated normally.

ISSN:1923-4287    

DOI:10.1139/cjr29-002

出版商:NRC Research Press    

年代:1929

数据来源: NRC

摘要:

In an investigation of the resistance of Portland cement to sulphate action a new form of hydrated tricalcium aluminate, with six molecules of water, was prepared by treating pure tricalcium aluminate with steam under pressure and drying the product over quicklime. This hydrate is crystalline and isotropic. It is stable at 100 deg. C., but at 275–300 deg. C. it gives up three-quarters of its water, forming a stable 1.5-hydrate. Some water is retained up to 1000 deg. C. Before the last of the water is expelled decomposition of the aluminate takes place. Recombination occurs at 1000–1100 deg. C.

ISSN:1923-4287    

DOI:10.1139/cjr29-003

出版商:NRC Research Press    

年代:1929

数据来源: NRC

摘要:

This paper covers work on B.C.G. vaccine carried on in Alberta over a period of approximately four years, during which time some 250 calves were made the subject of experiments. The vaccine was found to be entirely harmless, vaccinated calves developing normally and showing at autopsy no tuberculous lesions. Vaccinated animals in most cases reacted subsequently to the tuberculin test. Calves vaccinated with B.C.G. and immediately exposed to infection showed moderately increased resistance to tuberculosis over unvaccinated controls. Calves vaccinated with B.C.G. and subsequently kept under sanitary conditions for a period, in order to permit resistance to develop before exposure to infection, showed 80 per cent immunity as compared with 14 per cent for the controls. The tuberculous lesions found in vaccinated calves were in general much less pronounced as well as less numerous than those in unvaccinated animals. (F.E.L.)

ISSN:1923-4287    

DOI:10.1139/cjr29-004

出版商:NRC Research Press    

年代:1929

数据来源: NRC

摘要:

It is suggested that rust resistance in wheat may be due to the liberation of phenols in the host-cell upon the entrance of the fungus. A tentative method has been developed for determining phenolic compounds in wheat press-juice, including a critical study of the conditions for clarifying the juice with tungstic acid. The content of phenolic substances in wheat varieties has been found to bear some relation to rust resistance. Yellow pigments of the flavone type appear to be the main phenolic compounds present, and these are being investigated.

ISSN:1923-4287    

DOI:10.1139/cjr29-005

出版商:NRC Research Press    

年代:1929

数据来源: NRC

摘要:

In order to determine the effect of the ultra-violet and other components of sunlight upon certain marine organisms an apparatus was constructed with three different light filters. Seven marine organisms, varying widely in their habits with reference to light, were then exposed in the apparatus to various degrees of sunlight. Through one filter they received 91 per cent of the total sunlight, comprising both the visible range and the ultra-violet; through another, 82 per cent of the total, including the visible spectrum but no ultra-violet; through the third, 14 per cent of the total radiation, at the short-wave end of the spectrum. A fairly close relation was observed between the depth at which the organisms live and their susceptibility to short-wave radiation. In several cases ultra-violet light was found to be lethal in its effect. (F. E. L.)

ISSN:1923-4287    

DOI:10.1139/cjr29-006

出版商:NRC Research Press    

年代:1929

数据来源: NRC