308 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ IV, IV.

Let x axis represent the amounts of concentrate consumed and the ordinates
the total amounts consumed and digested on the same scale. The upper line stands
for total consumption and the lower line for total digestion (from both roughage
and concentrate). The lines are produced to meet the y axis and the points at which
they meet are carefully read. These have been shown in columns 2 and 3 of
Table VII. Obviously they represent the amounts consumed and digested from the
roughage (paddy straw) when no concentrate is supposed to be given. Their ratio
is shown in column (4) representing the digestibilities of the components of
roughage. Similarly the slope of the lower curve (column 5) stands for the
digestibility of the concentrate.

Each of the individual components, viz, dry matter, crude protein, ether
extract, etc., has thus been separately plotted out under 1 lb., 2 lb., and 3 lb.
combinations. These have been shown in separate graphs (Charts 2—7). In these
the mean under each group with its circle of error is also represented to indicate
the range of variation.*

* For accurate drawing the straight line of best fit can be obtained by least squares giving the
ordinates as well as the slopcs.