Letter | Published:

Statistical Aspect of the Production of Primary Lesions by Plant Viruses


MR. BALD points out in NATURE of June 15 (p. 996) that an attempt to fit the equation y = N(1 eax) to data obtained by Samuel and Bald1 meets with poor success, especially at high dilutions. Samuel and Bald plotted the logarithms of their counts against the logarithms of the dilutions and found that at high dilutions the points lay on a straight line with a slope of 0.6. It may be easily shown that the equation predicts a slope of unity. Data published recently by Price2, Chester3, Caldwell4 and Beale5, give experimental curves with approximately unit slope. This suggests that the discrepancies between Samuel and Bald's experimental counts and values calculated from the equation may in a large part be due to the fact that their data are at variance with other measurements in the literature.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Ann. App. Biol., 20, 70–99 ; 1933.

  2. 2

    Contrib. Boyce Thompson Inst., 4, 359–403 ; 1932.

  3. 3

    Phytopath., 24, 1180–1202 ; 1934.

  4. 4

    Ann. App. Biol., 20, 100–116 ; 1933.

  5. 5

    Contrib. Boyce Thompson Inst., 7, 37–53 ; 1935.

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.