ABSTRACTS
247
It has been found that by taking advantage of their behavior toward dyes in suitable dilutions
in a medium, all strains fall into one or the other of three groups or species.
Those strains which are slightly, if at all, inhibited in their growth on beef liver infusion agar
containing thionin in a 1—25,000 or 1—50,000 dilution or containing basic fuchsin in a 1—25,000
or 1—50,000 dilution belong to the Br. melitensis species.
Those strains which grow on the thionin medium but fail to grow on the basic fuchsin medium
belong to the Br. suis or porcine species.
Those strains which grow on the basic fuchsin medium but fail to grow on the thionin medium
belong to the Br. abortus (Bang) species.
By employing a medium containing thionin in the dilution mentioned and one containing basic
fuchsin in the proper dilution, the three known species of brucella can be distinguished from one
another.
On the basis of the present existing evidence, it is proposed that the genus Brucella be divided
into three main species, namely, Br. abortus (Bang), Br. suis (Traum), and Br. melitensis (Bruce).
Nutritive value of pasture, VI—The utilization by sheep of mineral deficient
herbage.
Messrs. H. E. Woodman and R. E. Evans, as a result of a series of experiments, described in an
article entitled "Nutritive value of pasture" and, published in the Journal of Agricultural Science,
Vol. XX, Part 4 of October, 1930, arrived at the following conclusions, which are of interest to stock-
owners in many parts of India, where mineral deficiencies are considered to be responsible for much
of the malnutrition and the degeneracy of stock which occurs, viz.:—
" In the consideration of the reason for the failure of grazing animals to thrive in regions of
mineral deficient pasturage, the standpoint may be taken that the failure may sometimes be due as
much to the energy deficient character of the herbage as to its deficiency in minerals. The starch
value of such herbage may be so low that animals, even when consuming it to the limit of
appetite, may not be able to secure sufficient net energy for normal development The further
question may also arise as to the method whereby mineral deficiencies cause the symptoms of malnu-
trition. Although it is clear that mineral deficiency must operate adversely by preventing normal
development of the skeletal structure, it is possible that the following factors may also be contributory:
(1) the digestibility of the organic constituents of the herbage may be depressed in the absence of an
adequate supply of minerals; (2) the lack of sufficient mineral matter may confer an unpalatable
character on the herbage, a circumstance which may react adversely on the appetites of the grazing
animals; (3) the physiological utilization of the digested nutrients may not proceed normally, if the
amount of minerals in the diet is deficient.
In the investigation which has been described in the present communication, an attempt has
been made to secure information which might furnish an answer to these and kindred questions. A
detail study has been made of the utilization by sheep of a sample of mineral-deficient herbage.
The latter consisted mainly of purple melick grass and brown bent grass, with a small amount of
sheep's fescue and traces of Yorkshire fog, sweet vernal grass, rough stalked meadow grass and florin.
Clover and other leguminosæ were not present, even in traces. From the chemical standpoint, the
herbage was deficient in total ash, the most serious mineral deficiencies being in respect of lime and
phosphoric acid. The supply of soda was also on the low side, whereas the percentages of potash,
magnesia and chlorine were similar to the amounts of these constituents in " normal" herbage.
The following main conclusion has been drawn. The results lead to the belief that the failure
of stock to thrive in mineral deficient pastoral areas cannot be explained by assuming that the low