200
ABSTRACTS
calves, and eight out of seventeen calves treated with
minimal infective doses. He believed that these animals
were immune in the way that the most large African game
animals within tsetse-fly belts are. Subsequent history
of these surviving animals, however, as indicated above
was different, and the author has consequently come to
the conclusion that "no method of immunization which
will enable East African domestic stock to thrive in tsetse-
fly belts has yet been devised". [F. N. R.]
The value of dogfish meal as a protein supple
ment. M. RHIAN, J. S. CARVER, R. W. HARRI
SON, and W. S. HAMM (1942). Bull.agric. Exp.
Sta., State Coll. of Washington, 416, 1-24.
VARIOUS experiments were carried out to determine the
effects of different methods of processing on the gross
valve of meals made from dogfish.
The data presented indicate that the commercial
dogfish meals available in Washington were of a low
nutritive value as judged by growth experiments carried
out on chicks. Other experiments were carried out to
determine the relative values of wet and dry methods of
processing the meals. Wet process meals were prepared
as follows: the fish were ground, cooked with live steam
at atmospheric pressure, pressed to remove oil and water,
and dried in a steam vacuum drier. The dry process meals,
were prepared by drying the fish in a steam-jacketed
vacuum drier and removing the oil by pressing the dried
product in a hydraulic press.
The wet processed meals gave as good results per unit of
protein as ordinary fish meals and very much better
results than commercial or laboratory dry process catfish
moal.
The data also suggest that the quality of fish meal
proteins deteriorates fairly rapidly after manufacture and
that it is very probable that the fish meals as used under
commercial conditions, are much poorer in value than
meals at the time of manufacture.
An initial trial with materials treated with formaldehyde
prior to processing suggested that such treatment may be
harmful to the resulting product. However, later trials
demonstrated that the harmful effect obtained in the
initial trial could not be attributed to formaldehyde
treatment.
The essential difference between the wet and dry pro
cess treatments of the fish meal used is that a large
amount of water soluble material is removed during the
wet-process. The hypothesis is put forward that the
wet-process meals may have lost some substance which is
either toxic to the chicks or which adversely affects the
protein.
A sample of commercial (dry-process) dogfish meal,
which was re-processed by the wet-process gave consider
ably better growth results in chicks than the original
type of meal.
From the results of this experiment in conjunction with
those of earlier work the authors conclude that, though
uric acid is not utilized by the chick, it is not harmful to
the feeding value of a food except that it affects the
determination of the protein content.
The average protein (N/6.25) of the commercial (dry-
process) dogfish meal was 77.3 per cent. and that of the
wet-process dogfish meal was 67.5 per cent. It is sug
gested that unadulterated dogfish meals of exceptionally
high protein content (N/6.25) especially with a high uric
content, are likely to be dry-process meals. [A. J. M.]
Various oils and fats as substitutes for butter fat
in the ration of young calves. T. W. GULLICK-
SON, F. C. FOUNTAINE and J. B. FITCH (1942)
J. Dairy Sci., 25, 117
THE comparative feeding value of vegetable oils like
coconut, peanut, corn, cottonseed and soybean oils, and
animal fats, such as butterfat, lard and tallow, for young
dairy calves was measured by the rate of gain in weight
and by observing the physical appearance and general
well-being of the animals. Calves were put under ex
periment at the age of one to two weeks. Fats or oils,
mixed at the rate of 3.5 lb. to every 96.5 lb. skim milk
and homogenized to give a product containing 3.5 per
cent of the fat or oil, were fed to the respective groups of
animals, with the following low fat content concentrate
mixture-dry beet pulp, 200 lb. ; dry skim milk, 50 lb.;
gluten milk, 50 lb. ; cod liver oil U. S. P., 25 to 35 cc.
and some alfalfa hay. Two control groups were run
simultaneously, (1) entirely on a fat poor ration, skim
milk (0.01-0.02 per cent fat) along with the following
concentrate mixture-ground molasses beet pulp, 100 lb.
dry skim milk, 50 lb.; starch, 50 lb. and cerelose, 25 lb.;
and (2) on whole milk not homogenized.
The periods
ranged from a few days to about six months. The
average daily intakes of nutrients per 100 lb. live weight
of calves fed various fats and oils were 1.62 lb. for the
whole milk, 1.82 lb. for the butter oil, 1.57 lb. for the
low fat, 1.83 lb. for the lard, 2.0 lb. for the tallow, 1.71
lb. for the coconut oil, 1.96 lb. for the peanut oil, 1.71
lb. for the corn oil, 1.59 lb. for the cottonseed oil, and
1.37 lb. for the soybean oil groups. The average daily
gain in the weight of calves of the respective groups were
1.43 lb., 1.22 lb., 1.07 lb., 1.17 lb., 1.24 lb., 0.96 lb.,
0.80 lb., 0.40 lb., 0.31 lb., and 0.32 lb.
The calves fed butter fat excelled those in all other fat
or oil groups in physical condition, general well-being
without any complaint of scour and in average gain in
weight. Corn-oil-cotton seed oil and soybean-oil fed
groups were the least satisfactory, and the animals were
most severely affected with indigestion or scour among
the other groups, and soms of them died.
Another significant difference noted between the
groups was the greater deposition of fat in the carcasses
of the milk-fat-fed calves. [B. C. R. S.]
Enzymatic production of bacterial polysaccharides.
M. STACEY (1942). Nature, 149, 639
SEVERAL investigators have reported the synthesis of
Polysaccharide by enzyme preparations obtained from
various species of spore-forming b acilli. The author
also describes some of his experiments, in this line, which
are of considerable importance in the study of the mecha
nism of symbiosis of yeast and bacteria.
He found that Leuconostoc mesenteroiles, grown in
symbiotic association with Succharomyces cerevisioe, forms
mucoid dextran more rapidly than when grown alone.
The production of this dextran, at one stage, is attri
buted to 'exocellular enzymatic action. The enzyme
system is, on the other hand, suggested to be sharply
stimulated by a factor elaborated in situ by the living
yeast cells.
The purified dextran [α] D + 180° in water contained N
0.5 per cent and gave only glucose on acid hydrolysis.,
[N. B. D.]
The value of the rapid whole blood—stained
Antigen Agglutination test in the eradication
of pullorum disease. R. F. GORDON and
G. C. BRAUDER (1942). Vet. Rec., 54, 275-9.
THE comparative value of the rapid whole-blood
agglutination test, using stained antigen, and the routine