ABSTRACTS
349
autoclaving destroys 33 to 67.5 per cent and sun drying causes a loss of 69.5 per cent.
It has been shown that enzymes are at least partly responsible for this loss. In storage
under practical conditions, losses of carotene are serious during summer. Ensiling is
an important method of preserving forage and preventing the loss of carotene. Carotene
is the principal pigment in the body and milk fat of cattle. Swine, sheep and goat tissues
do not contain any appreciable amount of pigment and their body fat is white. In the
grassfed animals, carotene is present in greatest quantity and one of the commonly
occurring off-flavours in milk termed ' oxidized ' is corrected when the ration fed is rich
in carotene. [ B. N. M.]
Pulmonary tuberculosis in man as a source of infection for cattle. F. W.
NIELSEN, AND N. PLUM (1940). Vet. J. 96
T HE question of transmission of tuberculous infection from man to cattle plays too
great a role to be ignored when undertaking work in connection with the eradica-
tion of tuberculosis in cattle. Two kinds of tuberculous infection are transmitted
from man to cattle, namely : (1) infection of cattle from man with tubercle bacilli of the
human type, and (2) infection of cattle from man with tubercle bacilli of the bovine type.
The authors describe the presence of tuberculous lesion in the mesenteric lymph
gland of a heifer with tuberculous infection of human type transmitted by one of the farm
attendants. Then they proceed to describe 17 cases of tuberculosis in which perfectly
healthy cattle have been infected from persons with open pulmonary tuberculosis due to
the bovine type of tubercle bacilli. The 17 herds which had been free from reacting
animals had 632 head of cattle in all, out of which 384 gave a positive tuberculin reaction
The authors enumerate the difficulties encountered in effecting the proper medical
examination of the suspected personnel of the infected farms and suggest that legal
measures be enacted to provide for this medical examination and that all tuberculous
persons owning or attending cattle have their infection type determined under Govern-
ment authority and that the Veterinary Directorate be notified at once of all cases in
which infection with bovine type is demonstrated. [ K. I.]
The colorimetric estimation of uric acid in fowl's excreta. J. C. D. HUTCHINSON
(1941). Biochem. J. 35, 81
T HE author has described a colorimetric method for the determination of uric acid
in fowl's excreta. This method is claimed to be more specific and less laborious
than other methods at present in use. It consists in extracting uric acid from air-dried
excreta with 0.5 per cent lithium carbonate solution. The uric acid is precipitated from
an aliquot of the filtered extract by the Benedict and Hitchcock ' ammoniacal silver
magnesium precipitant'. After removal of ammonia by a current of air the precipitate
is decomposed with 7 per cent lithium chloride in 0.125 N hydrochloric acid solution.
The decomposition of the precipitate by acid chloride not only removes the silver but
has the advantage of bringing down most of the colouring matter. The uric acid is then
finally estimated colorimetrically by the addition of Benedict's arsenophosphotungstic
acid reagent.
The author has tested the method by recovering different quantities of uric acid
from ' nearly uric acid free ' fowl's excreta obtained by separating mechanically uric
acid from normal excreta. The amount of uric acid added was recovered quantitatively
over the whole range of conditions likely to be encountered in practice. The specificity
of the method has also been tested by adding uric acid and. ammonium urate to sheep's
and human faeces, as it is difficult to obtain fowl's excreta completely free from uric
acid. These tests show that the method is highly specific and gives good results under
conditions which caused a failure of the methods of Woodman [1924] and of St. John
and Johnson [1931]. [S. B.]