WOOL-GROWTH IN SHEEP AS AFFECTED BY DIET              261

In so far as fibre-lengths affect the appearance of staple-length in such wools,
these figures illustrate one aspect of the difference between the groups. The
change in production, considered from the standpoint of fibre-length alone, was
marked in the basal-ration group, and the feeding of the starch supplement con-
ferred a small but significant advantage in respect of growth in fibre-length.

If the short fibres are included, this distinction between the groups tends to
be diminished and the effect of the different nutritional levels is reduced. The
position in respect of mean fibre-lengths with short fibres included is summarized
in Table VI.

                                        TABLE VI.

                 Mean fibre-lengths, including short fibres.

This points to the conclusion that the difference in production on the sample
areas was expressed more in other ways than in mere length of fibre grown, so that
the other factors of average fibre-fineness, and, possibly, the number of fibres
produced (i.e., number of active follicles) have to be taken into consideration.

(d) Average fineness. After counting and measuring the fibres, the sub-samples
were washed in benzene and their clean-dry weights were determined. From the
calculated total lengths of fibre and these weights, the values for fineness expressed
as length (in cm.) per unit weight (mgm.) were derived.

Even under ordinary conditions, some change in fineness might be anticipated
in all the animals, as the growth-periods cover two different stages in the matura-
tion of the lamb's coat. The two groups at the outset were well balanced as
regards fineness, and it will be seen that the different metabolic levels produced
markedly dissimilar effects. In all animals, except No. 19 (Group II), the wool
was distinctly finer at the end of the feeding period, and there is some general