Preparation of Leaf Epidermis for Topographic Study

Epidermal strips of leaves of the Gramineae can be prepared using the following technique: The mature leaf is dipped in boiling water to kill the cells, and decolorized in boiling 70% alcohol. It is cleared and softened in 88% lactic acid. Epidermal, mesophyll and vascular tissue is removed from a selected constant area of the leaf leaving an epidermal strip 1-3 cm in length. This is inverted on a slide, stained in lactopheno-cotton blue, and destained in 88% lactic acid. Transverse and longitudinal sections of the strip are obtained at this stage. The epidermal strip is finally mounted on a slide in 88% lactic acid. The preparation is photographed with a 35 mm camera using transmitted light, and a yellow filter in the microscope lamp. Photomicrographs of known enlargement are then prepared from which accurate measurements can be recorded. The technique is applicable to both fresh and herbarium material.     

The estimation of optimum applications of a quantitative factor to crops grown in rotation

Summary Given certain prior information about residues from earlier applications of a quantitative factor Q to crops grown in rotation, this paper shows how relatively simple experiments can be used to provide estimates of the optimum applications of Q to successive crops; the estimates obtained allow for the presence of residues. The prior information in the particular case discussed is that if x units of the factor are applied then the residues one, two, three ...t... seasons later are rx, rpx, rp²x, ...rp^t–1x..., where r and p are constants such that 0r<1, 0p<1.     

Medical Students in Canadian Universities: Report of Statistics, 1965-66

Enrolment in the 12 Canadian medical schools in 1965-66 reached a new high of 4023, an increase of 3.8% over 1964-65. The percentage of women among medical students (11.4%) was close to that for the preceding two years. The decline in the numbers of students from outside Canada continued into the present year; in 1965-66, 9.1% of medical students were non-Canadian. This decline has been primarily in the number of students from the U.S.A. The number of students from Commonwealth countries has shown a steady increase over the seven-year period under review; in 1965-66 they make up nearly one-half of all non-Canadian students. It was noted that 27% of overseas students came to Canada under governmental or intergovernmental sponsorship. Of the Canadian students, 95% came from the “home” provinces of the medical schools.