摘要:

Further studies of the pollen constancy of hive bees and the wild bee visitors to apple blossoms, in continuation of those previously published (1, 2) are reported. Only hive bees and variousAndrenaspp. appeared in significant numbers in this study. The latter show a much lower degree of constancy than the former, confirming previous work. The wide difference between the complex of insect pollinators at Macdonald College and that of Kings County, Nova Scotia, is discussed. The highly polytrophic character of the common insect pollinators of the apple is emphasized.

ISSN:1923-4287    

DOI:10.1139/cjr34-024

出版商:NRC Research Press    

年代:1934

数据来源: NRC

摘要:

A total of 227 isolates ofHelminthosporium sativumand 286 ofFusariumsp. (culmorumtype) were obtained from the diseased crown tissue of wheat stubble in five fields located in the black soil belt of central Alberta, and an attempt was made to determine their relative virulence on wheat seedlings and on mature plants. The experiment was carried out under greenhouse conditions, with a range of soil temperature. Sterilized, artificially infested soil in open pot culture was used. The results indicated that theHelminthosporiumisolates were as a rule moderately to weakly pathogenic, and that most of theFusariumisolates were only weakly pathogenic to wheat plants in the seedling stage. Some isolates of each pathogen exhibited extreme virulence, but judging from the results on seedling plants, virulent strains were rather rare in the fields studied. On mature plants both fungi showed about equal degrees of virulence, which was on the whole weak, and the results were not considered significant for the purpose of the study. More isolates of the greater degrees of virulence were obtained from certain fields than from others. In view of the great susceptibility of seedling plants in sterilized re-infested soil and the variable results, presumably caused by association effects of contaminants of the soil in open pot culture, it was concluded that the object of the study could not be attained by means of data based on the seedling stage, or by the technique employed. The possibility of significant results being secured in sterilized re-infested soil, protected from contamination, and based only on mature plants, is discussed in relation to the root rot problem.

ISSN:1923-4287    

DOI:10.1139/cjr34-025

出版商:NRC Research Press    

年代:1934

数据来源: NRC

摘要:

A study was made of organisms concerned with the red discoloration of salted hides, also termed "red heat", which defect may occasion loss in the leather industry through spotting and weakening of the fibre. Red halophilic sarcinae were isolated from Argentine hide. From Canadian hides showing red discoloration, two species of pleomorphic rods were isolated as active agents. One of these, occurring on salted cowhides, was found to be similar toSerratia salinaria(Harrison and Kennedy) Bergeyet al., a source of reddening of cured codfish in eastern Canada. The other organism causing discoloration, isolated from buffalo hide, was regarded as a new species and designatedSerratia cutirubran.sp. Both of these halophilic organisms, owing to their proteolytic action, are considered capable of greater damage to hides than the red sarcinal types which are non-liquefying, and which may also be present on Canadian hides. Non-chromogenic halophilic bacteria were also isolated from discolored hides. These develop at a lower salt concentration range than the red organisms and are probably less active in causing injury to fibre in well salted hides.

ISSN:1923-4287    

DOI:10.1139/cjr34-026

出版商:NRC Research Press    

年代:1934

数据来源: NRC

摘要:

The investigations described in this paper were carried out during the period 1928–1933, and deal with the egg parasite,Trichogramma minutumRiley, with special reference to its field of usefulness in the biological control of the oriental fruit moth (Laspeyresia molestaBusck.) in Ontario. This cosmopolitan parasite is a factor of considerable importance in regulating the abundance of the fruit moth in southern New Jersey, but appears to be of little practical significance in the natural control of the pest in Ontario. Under certain conditions of weather and host abundance, parasitism may be increased materially by the liberation ofTrichogrammain the orchards but, in general, the results are not dependable. A large number of experiments were conducted utilizing three biological races of the species. The technique employed in the work and the results obtained are given as well as a number of important observations on the habits and biology of the parasite.

ISSN:1923-4287    

DOI:10.1139/cjr34-027

出版商:NRC Research Press    

年代:1934

数据来源: NRC

摘要:

Some of the reactions of the tertiary chloride, obtained as a primary product by the action of thionyl or acetyl chloride on β, β-dimethylanhydracetonebenzil, are described.

ISSN:1923-4287    

DOI:10.1139/cjr34-028

出版商:NRC Research Press    

年代:1934

数据来源: NRC

摘要:

The oxidation of allyl alcohol by potassium permanganate in acid solution results in the formation of three molecules of formic acid; up to this point the successive steps involved are favored by acidity of the solution, such that the velocity of the reaction varies directly as the concentration of sulphuric acid. Also the rate of oxidation varies directly as the concentration of the oxidizing mixture. The most rapid part of the reaction is the absorption of the first six equivalents of oxygen, the slowest being that of the last six of the total of 16 concerned. A mechanism is suggested.

ISSN:1923-4287    

DOI:10.1139/cjr34-029

出版商:NRC Research Press    

年代:1934

数据来源: NRC

摘要:

The sorption of benzene vapor by alumina gel has been measured over a range of temperature and concentration. It has been found that divergent sorption values obtained with gels differing in residual water approach a constant value when expressed per gram of active alumina. Straight lines are obtained when the logarithm ofx/mis plotted against the logarithm of the vapor pressure. Patrick's equation is approximated for lower relative pressures. Comparison of the results obtained with benzene with those previously obtained with water fails to show that hydration or "chemical" forces play any part in the sorption of water by alumina. The gel holds a larger volume of liquid benzene at low partial pressures.

ISSN:1923-4287    

DOI:10.1139/cjr34-030

出版商:NRC Research Press    

年代:1934

数据来源: NRC

摘要:

A sample containing 50 mgm. of radium bromide, prepared from ore obtained from the Echo Bay deposits in Canada, was tested for mesothorium impurity by the gamma ray absorption method. The material was found to be free from mesothorium within the limits of the experimental error, 0.2% radiation equivalent.As a confirmatory test a number of samples of the ore were analyzed for thorium in the National Research Laboratories, Ottawa. Quantities of thorium up to 0.07% of the uranium content were found, indicating a possible mesothorium impurity in the finished radium of 0.021% radiation equivalent.

ISSN:1923-4287    

DOI:10.1139/cjr34-031

出版商:NRC Research Press    

年代:1934

数据来源: NRC

摘要:

The experimental results of R. W. Wood are compared with theory using the model of free electrons perturbed by the periodic lattice potential. All relevant data are collected in a table in which it is seen that in sodium, potassium, rubidium and caesium the wave-length of the upper limit of the absorption band in the visible and near ultra-violet is proportional to the square of the lattice constant, while lithium occupies an anomalous position. The facts at present available do not permit a completely definite test of the absolute values of these wave-lengths given by the theory.

ISSN:1923-4287    

DOI:10.1139/cjr34-032

出版商:NRC Research Press    

年代:1934

数据来源: NRC

摘要:

The investigation demonstrates that errors of appreciable magnitude may occur in the measurement of angles of primary triangulation by certain observers, owing to variable personal equation of bisection. A simple method of eliminating these errors is described.

ISSN:1923-4287    

DOI:10.1139/cjr34-033

出版商:NRC Research Press    

年代:1934

数据来源: NRC