NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
T. W. M.
CAMERON
317
rather than to confine oneself to a single method. Control may be nation-
wide or it may be individual. Individual control is at best a palliative, and
compaigns directed over a wide area are infinitely more satisfactory. This
not only involves cooperation between veterinarians, agriculturists, adminis-
trators, and parasitologists, but it involves careful coordination as well.
A central authority and enabling legislation are almost essential, but the
legislation to be successful must come as the result of a demand from the
majority of the farmers involved. A central laboratory with a good informa-
tion service is also desirable, with adequately staffed branch or associate
laboratories throughout the country.
Control measures consist in breaking at some point or another, the es-
sential life-cycle of the parasite. If more than one point be attacked, the
chances of successful results are increased.
These measures may be discussed conveniently in several groups, although,
it must be understood that such a hard and fast division as is here adopted,
does not occur in nature and that methods described under one may be equally
applicable under another.
The parasite may be attacked at one or other of the following points in
its life-cycle:
A. While in the ovum or as a young developing larva.
B. During the developed infective stage, which does not grow and
' rests ' until it enters the host.
C. Before entrance of this larva into the host.
D. Within the intermediate host or vector, within which A. and B.
may be found and which may be the means of entry to the host.
E. During the parasitic stages in the host.
These methods aim at the elimination of the parasite entirely. How-
ever, we know that disease depends on numbers and other factors and it is
well also to discuss what these are and how the numbers or the effects of the
parasite may be reduced.
A. METHODS OF DESTROYING THE EGGS OR PRE-INFECTIVE LARVAE
These are those stages of the parasites passed in the faeces as well as the
subsequent stages which develop therein. (In a small minority of cases the
larvae are not passed in the faeces, but may leave by the mouth or the urinary
system or be abstracted from the blood by blood-sucking animals, or may
come to rest in the host's muscles). As we know of no efficient method of
destroying the eggs in the host (except in the case of some of the trematodes)
this division is accordingly mainly concerned with manure and its treatment.
It is not a new subject, having been advocated for years in connexion with
human hookworm disease, but curiously enough very little indeed has been
done about it in connexion with parasites of animals in which it is infinitely
more important.
There are two ways of treating manure. The first is to disregard its
parasite content and concentrate on its dispersal in such a way as to keep
it out of harm's way. The second is to treat it in such a way that its parasite
content is destroyed. Some twenty years ago, the late Dr Maurice C. Hall
stated that this subject offered a field for a large amount of investigation but
this investigation had not been done,
T. W. M.
CAMERON
319
is now almost routine practice. Dry quarters for any species of animal will
always assist in reducing internal parasitism.
In the open, short grass assists drying and is frequently of value in re-
ducing the infectivity of pastures, as of course, is drainage. Very wet pas-
tures, however, are not suitable environments for the development of most
nematodes (except Dictyocaulus of horses, sheep, and oxen). Damp pastures
are more generally favourable for parasitism and every effort should be made
to render them unsuitable for the development of eggs into larvae.
(d) Chemical treatment.—Comparatively little has been done to find
chemical methods of destroying the free-living stages of parasites. It is a
problem which presents many difficulties, probably the greatest of which is the
fact that the eggs and larvae are always in close contact with faeces, soil,
or grass, and many chemicals which might be used, are partially or completely
counteracted by contact with organic matter. Nevertheless, chemical control
of all the free-living stages does appear to have considerable practical possi-
bilities.
It offers the opportunity of using the faecal material as manure and even
of enriching the manurial value and it does not necessitate special equipment.
This method has been sporadically used with a certain limited success
in some human hookworm areas, the chemicals employed being kainit, lime,
and some nitrogenous fertilizers such as nitrate of soda, sulphate of ammonia,
and calcium cyanamide.
The potential advantages of such a method of destroying the eggs and
larvae of bursate nematodes seemed so great that a series of investigations
on this subject was inaugurated in the Institute of Parasitology a few years
ago with the help of the National Research Council of Canada.
As a test object the eggs of horse sclerostomes were used. The nomadic
life of wild horses in country exposed to extremes of temperature has necessit-
ated their bursate nematodes evolving an extreme hardiness both as eggs and
as infective larvae. This resistance to extremes of temperature appears to
be correlated with resistance to other unfavourable conditions. It is, therefore,
probable that the majority of chemicals which will destroy the eggs, and larvae
of horse sclerostomes will also be lethal to the free living stages of hookworms
and other bursate nematodes. That this is so has been confirmed for a few
chemicals with dog hookworms. However, the observations which are dis-
cussed here have all been made on horse sclerostomes.
F
FLEECE DENSITY AND THE HISTOLOGY OF THE
MERINO SKIN*
BY
H. B. CARTER, B.V.Sc.
Division of Animal Health and Nutrition, Council for Scientific and Industrial
Research
(Reprinted from the Australian Veterinary Journal, Vol. XV, No. 5, October 1939)
INTRODUCTION
T HE study of morphological variations in the fleeces of the important
breeds of domestic sheep has in general been made without reference
to the fundamental histology of the skin within which the fibres are
formed and by which they are maintained, normally, in a state of active growth.
The literature relating to the histology of ovine skin is very limited, and the
observations recorded are mainly of a general academic nature for the purposes
of comparative zoology. Such studies scarcely bear any direct relation to
specific problems of sheep husbandry and economic wool production. The
trend of histological work has seldom passed beyond the general observation
of the individual fibre and follicle with the associated sudoriferous and sebace-
ous glands, though a small series of studies has been made of the embryology
of these structures. The specific and detailed histology of the skin of any single
breed has only once been recorded [Tänzer, 1926] in such a manner that the
facts can be considered a valuable aid to the solution of problems which face
the practical breeder. The Merino has been comparatively neglected in this
respect, and the relative absence of useful detail regarding skin structure
and its variations in this breed constitutes one of the present most serious
handicaps to progress in biological research on many problems of wool pro-
duction, particularly in the field of genetics.
It is the aim of this brief paper to draw attention to the potential value of
histological studies of the Merino skin in leading to a more complete under-
standing of the fleece and its constituent fibres. It is believed that the direct
study of skin structure when properly related to the appropriate fleece charac-
ters will provide one of the most valuable aids to research in progressive
breeding for the improvement of Merino wool that is available to the scientific
investigator. As an illustration it is proposed to consider some fundamental
aspects of the follicle population in the skin and to indicate their significance
in relation to fleece density in the Merino. It must, however, be accepted
that for the purpose of this paper the cardinal fact on which the measurement
of fleece density depends and in terms of which the widest variations may
occur in the Merino, is the number of fibres per unit area of skin. It is to this
aspect of fleece density alone that reference will be made here. Nor will the
specific economic importance of this character of the Merino fleece be considered
beyond stating that it has always been one of the most important aims of the
Australian breeders to improve the density of the Merino fleece and by so doing
to increase the total amount of wool produced by their flocks.
* Paper presented at Annual General Meeting A. V. A., August, 1939,
( 320 )
H. B.
CARTER
323
then, the two sheep were by no means similar. Without the use of histologi-
cal methods these differences would have been concealed. Further more,
variations were also noted in the arrangement of the population. In the
animal with the wider ratio the follicles were arranged in neatly cir-
cumscribed clusters, whereas in the skin of the animal with the narrower
ratio the follicles were relatively more scattered and the grouping ill-
defined. Observation of the arrangement and grouping of follicles therefore
may provide a fourth criterion for comparative studies.
Within the limits of a single flock considerable variation occurs in these
four aspects of the follicle population. No animals have so far been encounter-
ed that are even approximately comparable in all respects, though several
instances have been noted where a fair degree of similarity was apparent.
It must be admitted, however, that sufficiently large numbers have not been
examined yet for such individual differences to be adequately classified.
In spite of this, there is much to suggest that these histological determinations
will provide most useful criteria for genetical experiments.
The value of Merino skin as experimental material will be considerably
enhanced when studies have been made to define in detail the relationship
between skin structure and the fibres of the growing fleece. For instance,
it is very probable, though by no means proved that the degree of uniformity
in fibre length and fineness could be to some extent anticipated by a considera-
tion of the P : (P+S) ratio. From this point of view the ratio may be regarded
as indicating the degree of blending of two distinct fibre populations, viz.
a coarse fraction consisting mainly of primaries, and a fine fraction consisting
of secondary fibres. Furthermore, since primary follicles alone have
sudoriferous glands associated with them and possess also the largest and
most obvious sebaceous glands, it is conceivable that variations in the
absolute and relative numbers of the follicle types would influence appreci-
ably the quantity and chemical characteristics of the ' yolk '.
If these and other probable relationships between different types of skin
and fleece structure can be established on a proper basis, then the study of
Merino skin histology must come to occupy an important place in research
aiming to effect an improvement not only in quantity, but also in the quality
of our wool.
REFERENCES
Tänzer, E. (1926) : ' Haut und Haar beim Karakul in rassenanalytischen Vergleich'.
Otto Thiele : Halle
Carter, H. B. (1939): ' A Histological Technique for the Estimation of Follicle Popu-
lation per Unit Area in the Sheep ' (unpublished).
REVIEW
The Breeding of Herbage Plants in Scandinavia and Finland. Joint
Publication No. 3 of the Imperial Agricultural Bureaux, Great Britain, 1940.
Price 4s.
A RRANGEMENTS have been made between the various Imperial
Agricultural Bureaux whereby any publication upon the preparation of
which two or more Bureaux collaborate shall be included in a new series
entitled Joint Publications. It has been decided to regard the earlier Joint
Publications on " Vernalization and phasic development of plants " and
" Erosion and soil conservation ", as Nos. 1 and 2 in this series. Other Joint
Publications produced in recent years but already out of print have not been
given numbers in the series.
The Imperial Bureau of Plant Breeding and Genetics and the Imperial
Bureau of Pastures and Forage Crops have now produced Joint Publication
No. 3, entitled " The breeding of herbage plants in Scandinavia and Finland ".
It is a symposium consisting of a series of articles by acknowledged specialists
in the respective countries. G. Nilsson-Leissner, F. Nilsson, E. Akerberg
and R. Torssell contribute articles on work in Sweden, H. N. Frandsen, H.
Wexelsen and O. Pohjakallio on Denmark, Norway and Finland respectively.
Each article reviews recent developments in the countries concerned,
including details of the most recent improved strains of grasses, clovers and
lucerne, and the methods used in producing them, as well as a contribution on
the application of cytology to herbage plant breeding. The articles vary
from 5 to 35 pages in length and are mostly quite detailed, each being provided
with a mass of tabular data and selected bibliographies. The Scandinavian
countries are recognized authorities on grassland and breeding problems and
the bulletin provides an invaluable outline of achievements up to date. This
is made specially clear by a useful summary of the entire contents of the bulle-
tin which appears at the beginning, before the presentation of the individual
articles. Another useful feature is the provision of a list of addresses of the
research stations concerned and of maps illustrating their locality.
The bulletin covers some 125 pages and is obtainable from either Bureau
at the moderate price of 4s. Standing orders for Joint Publications should
be placed with the Secretary, Imperial Agricultural Bureaux, 2 Queen Anne's
Gate Buildings, London, S. W. 1.
( 333 )
THE CLASSIFICATION OF THE STREPTOCOCCI OF BOVINE
MASTITIS
THE following note by Dr F. C. Minett *, Director of the Research Institution
in Animal Pathology, Royal Veterinary College, Camden Town, London,
N. W. 1, and Dr. R. B. Little, of the Rockefeller Institute of Medical Research,
Department of Animal and Plant Pathology, Princeton, New Jersey, U. S. A., is
reproduced from the Australian Veterinary Journal, Vol. XV, No. 3, June 1939. It is
being published simultaneously in several scientific journals throughout the world
in an endeavour to bring about a very desirable standardization in the methods
of identifying the streptococci of bovine mastitis.
' The purpose of this note is to call the attention of workers who are interested
to a project initiated by one of us (R. B. L.). The necessity for trying to
get some orderly arrangement of the streptococci which may be associated
with bovine mastitis has long been obvious. Not only is this so on the
grounds of bacteriological nomenclature, but, unless investigations in
different parts of the world use the same designations, it is difficult or
impossible to make those comparisons which are essential for a proper
understanding of the subject and in consequence scientific progress is
impeded. To give an example. The term ' Streptococcus
mastitidis'
has been used in the past for more than one kind of mastitis streptococcus,
whereas in fact it is now known that there are several kinds of streptococci
recognized by experienced workers as capable of causing different forms
of the disease. Moreover, only one of these forms is known to spread
easily in a herd. The subject of classification, therefore, has a clear
relation to preventive and clinical veterinary medicine.
' Briefly, we have decided to ask those who are studying mastitis to communicate
with us. Persons resident in the American continent and Japan should
write to Dr. Little, while those in Europe and the British Empire are
requested to get into touch with Dr. Minett *. Persons who are interested
would then be requested to re-examine their cultures (1) by means of a
group B standard serum which would be issued, (2) by certain relatively
simple cultural and biochemical methods. Mimeographed copies of
suggested methods for carrying out these tests and forms for recording
the results would be sent out at the same time, to be returned as soon as
possible to Princeton or to Camden Town as the case may be. Cultures
giving ' atypical' reactions should be sent for re-examination to one or
other of these centres. Type strains would be issued on request for purposes
of comparison. Later on, the results of the enquiry would be circulated
to all concerned, and then, if the majority of workers agreed, they could
be published in summary form, with particular reference to ' atypical'
strains.'
* At present Director, Imperial Veterinary Research Institute, Mukteswar, India.
( 334 )
ERRATA
[THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY, VOL. X,
PART II, JUNE 1940]
Page 141, line 10 from bottom, for 'above' read 'in Table VII'
Page 144, line 15 from bottom, for 'above' read 'in Table IX'.
Page 145, last line, for 'Table X' read 'Tables X and XI'.
Page 146, Table X, Group I.a., Remarks column, for 'Slaughtered on April
1939' read 'Slaughtered on 1 April 1939'.
Page 148, line 5 from bottom, for 'Table XXIII' read 'Table XIII'.
Page 149, Table XIII, Goat No. 237, Material column, for 'Do. heated
50-60°C for 45 minutes' read ' Do. heated 55-60 °C for 45 minutes'.
Page 178, line 9 from bottom, after the word 'respectively' add 'Tables
XXXVIII and XXXIX'.
Page 212. last line, for ' y = α.w'read'y = αw P'
Page 215, line 5 from bottom, after '10' add '198-209'
Page 223, first line, for 'NORAMAL' read 'NORMAL'.
Page 242, line 14 from bottom, for 'tropical' read 'topical'.
Page 242, line 9 from bottom, for 'espirit' read 'esprit,'.
( 335 )
ORIGINAL ARTICLES
VITAMIN A STUDY OF GHEE*
PART IX. RECOVERY OF REVERSIBLY OXIDISED VITAMIN A BY
TREATMENT WITH HYDROGEN UNDER PRESSURE
BY
S. V. GOVINDARAJAN
AND
B. N. BANERJEE
Department of Biochemistry, Indian Institute of Science, Bangalore
(Received for publication on 4 March 1940)
(With Plate XXIII)
I T has been observed that the vitamin A of butterfat is fairly resistant
to heat, and that it is not completely destroyed until a considerable period
of time has elapsed [Osborne and Mendel, 1920 ; Banerjee and Dastur, 1937].
That the vitamin is protected by antioxidants in the fat is well recognised
[Mattillm, 1931]. The rate of destruction of these antioxidants and of the
vitamin depends on the temperature of heating, the acidity of the ghee, and
other factors. Temperatures higher than 115°C and free acidity above 0.5
per cent (oleic acid) cause rapid loss of vitamin A in ghee.
When ghee is heated in air for a certain period of time (the induction
period) there is little or no decrease in the vitamin content, but subsequent
to this period, the destruction is rapid due to oxidation changes. Banerjee
[1938] records that when hydrogen gas is bubbled through ghee at such a
stage, a gradual rise in vitamin content to nearly the original value occurs
and the vitamin level remains steady during subsequent heating.
Since the oxidation changes are rapidly brought about by heating, similar
changes might be the cause of vitamin losses observed during storage. This
recovery of vitamin activity after bubbling in hydrogen suggests that the same
change could be brought about by applying the treatment to old ghee samples.
In the ordinary way bubbling in hydrogen at atmospheric pressure needs
10-15 hours to effect the change and this long period of heating is bound to
affect the flavour disadvantageously.
The present work was undertaken in order to investigate the effect of
hydrogen under pressure on the vitamin content. The apparatus consisted
of a steel autoclave (Gallenkamp No. 1606) provided with an outer jacket
containing oil heated to any desired temperature. The ghee was kept inside
the pressure chamber in a stainless steel vessel, and hydrogen under pressure
* The previous parts of this series have appeared in Agriculture and Livestock in
India.—Part I: Vol. 5, p. 382 ; Part II: Vol. 6, p. 154 ; Part III: Vol. 6, p. 274 ;
Part IV : Vol. 6, p. 433 ; Part V : Vol. 7, p. 24 ; Part VI: Vol. 7, p. 697 ; Part VII:
Vol. 8, p. 153 ; Part VIII: Vol. 8, p. 158.
( 335 )
A2
336
Vitamin A Study of Ghee
was bubbled into it through a tinned brass tube which thus stirred the liquid
ghee thoroughly. The autoclave was fitted with a safety valve and pressure
gauge and the temperature inside could be read on a thermometer suitably
placed in the lid. Samples of ghee were drawn off at intervals via the gas
inlet tube by opening the cock. The changes taking place during the treat-
ment with hydrogen were followed without disturbing the closed system.
Any fall in pressure subsequent to the drawing of a sample was made good
by passing in more gas through the same inlet tube.
The vitamin A measurements were made colorimetrically on the blue
colour formed by the unsaponifiable fraction with antimony trichloride
reagent, and expressed as blue units per gram of butterfat. The yellow
values were obtained by qualifying the yellow colour of the chloroform
solution of the unsaponifiable matter in Lovibond units. The results are
given in Table I.
TABLE I
Regeneration of vitamin A at different temperatures and pressures on treatment
with hydrogen
Source of sample
Imperial Dairy Institute
Kathiawar
Temp.
°C
..
110
„
„
„
„
„
„
„
..
80
„
„
Pressure
atmos.
..
20
„
„
„
„
10
„
„
„
10
„
„
Time of
reaction
hr.
0
0.5
1.0
4.0
11.0
19.0
1.0
2.9
4.0
0
0.5
1.0
5.0
Lovibond
Blue
value
Yellow
value
(per gram of
butterfat)
27.5
34.1
35.2
27.5
17.6
20.9
33.0
34.1
30.8
4.4
8.8
9.9
15.4
1.6
1.6
1.4
1.0
1.0
0.8
1.4
1.2
1.1
0.8
0.8
0.7
0.4
S. V. GOVINDARAJAN AND B. N. BANERJEE
337
TABLE I—contd.
Source of sample
Kathiawar—contd. . .
Temp.
°C
90
„
„
„
100
„
„
Pressure
atmos.
10
„
„
„
„
„
„
Time of
reaction
hr.
0.5
1.0
2.0
6.0
1.0
2.0
7.0
Lovibond
Blue
value
Yellow
value
(per gram of
butterfat)
7.7
11.0
8.8
7.7
14.3
11.0
8.8
..
0.8
0.7
..
0.7
..
0.3
At a pressure of 20 atmospheres and a temperature of 110°C the time
necessary to recover the vitamin A activity was reduced to less than one hour.
The optimum conditions to effect the changes to the same extent appear to
be to heat for one hour at 100°C with hydrogen at 10 atmospheres pressure,
and these have been adopted in subsequent work. At 80°C and 90°C the
changes take place much slower than at 100°C and hence the range 95-100°C
has been taken as the convenient one.
The heat treatment of one hour in an atmosphere of hydrogen was not
considered a drastic treatment. The flavour of the ghee was not affected in
most of the samples and slightly improved in others.
Influence of acidity on the regeneration of the vitamin.—Acidity is one of
the main factors catalysing the oxidation of fats. The principal cause of
rancidity is the formation of free fatty acids and aldehydes, which impart an
acrid taste and smell to rancid ghee. Vitamin A is unstable towards oxida-
tion and is susceptible to destruction in the presence of abnormal amounts of
free acids in ghee. Some of the unsaturated fatty acid residues of rancid
butterfat have been oxidised to peroxides. The determination of the peroxide
value has been considered of value as a measure of the oxidised state of the
fat. Since oxygen in the peroxide form is chemically reactive, its destructive
action on vitamin A and on the antioxygenic substances protecting the
vitamin must be considered when assessing the keeping quality of ghee. It
was considered desirable to study the effect of hydrogen treatment on the
peroxide value and on the acid values of different ghee samples. The vitamin
A recovery in ghee whose acidity was artificially increased by the addition
of oleic acid was also studied.
The determinations of the peroxide were made according to Lea's method
[1931], the active oxygen being expressed in terms of ml. 0.002 N sodium
thiosulphate solution per gram of butterfat. The acid value was expressed
as per cent oleic acid.