Abstract
Results and discussion continued.p (d) Difference between physiological and piu-ely chenaical temperature- velocity reactions Physiological processes Growth or permanent bulk increase Mitosis (e) The reactions of definite mitotic stages General survey 6 DURATION OF THE SEVERAL MITOTIC STAGES sampling, one in which the mitotic stages may be definitely marked according to arbitrary but fixed standards, and one which will yield numerous samples in order that the average values calculated may have relatively small probable errors.The method herewith presented is a statistical one based upon stage counts and their classification, within selected microscopic fields taken from closely related and similarly active tissues through a regular suc- cession of observation-instants.The calculations and comparisons shown on the accompanying Method Chart demonstrate the generality and vaUdity, for the purpose designed, of the principle so based, and which is employed in determining the measurements reported in this paper.PROOF OF PRINCIPLE: HYPOTHETICAL CASE.The principle here employed is as demonstrable as a geometrical theorem.For the purpose of such proof the case here first presented (see L Method Chart) is an hypothetical one in which the mitotic prog- ress is plotted for each of a series of related cells, through an evenly graduated time-scale.Among the cells thus plotted there is fluctuation in (a) the mitotic index^(M.I.), ( 6) the duration of successive stages within the same cell, and (c) the duration of stages of the same order in different cells.This situation, as will be seen later, approximates the actual condition of mitosis in the dividing root-tip cells of the onion.'Professor C. S. Minot first used and defined the term mitotic index, "Age, Growth, and Death."Pop.Sci.Mo. 71: 510, 1917.It is the percent-measure of the total number of cells showing mitotic activity in a given sample tissue.
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Claims 1
Claim · model-written summary
Stage counts and classification in microscopic fields were presented as a valid method for measuring mitotic stage durations.
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Verbatim
e0“The calculations and comparisons shown on the accompanying Method Chart demonstrate the generality and vaUdity, for the purpose designed, of the principle so based, and which is employed in determining the measurements reported in this paper.”
t0“common onion”