NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
March, 1949] ZAL, R. KOTHAVALLA, C. P. ANANTA KRISHNAN AND T. M. PAUL 73
TABLE II—contd.
Table for correcting Lactometer reading to 60º 1.
Temperature in degrees
Farenheit
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
To be added to the L.R.
Percentage of fat observed
3
4
5
6
7
8
Corrections to correct L.R. to 60ºF.
0.1
0.3
0.5
0.6
0.7
0.9
1.1
1.2
1.4
1.5
1.7
1.9
2.0
2.2
2.3
2.5
2.7
2.9
3.0
3.2
3.4
3.6
3.8
4.0
4.2
0.1
0.3
0.5
0.6
0.7
0.9
1.1
1.2
1.4
1.5
1.7
1.9
2.1
2.3
2.5
2.7
2.9
31
3.2
3.4
3.6
3.8
4.0
4.2
4.4
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.5
1.7
1.9
2.1
2.3
2.5
2.7
2.9
3.1
3.3
3.5
3.7
3.9
4.1
4.3
4.5
4.7
4.9
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.5
1.7
1.9
2.1
2.3
2.5
2.7
2.9
3.1
3.3
3.5
3.7
3.9
4.1
4.3
4.6
4.8
5.0
0.2
0.4
0.6
0.8
1.0
1.2
1.5
1.6
1.8
2.0
2.2
2.4
2.6
2.9
3.1
3.3
3.5
3.7
3.9
4.1
4.3
4.5
4.7
4.9
5.1
0.2
0.4
0.6
0.8
1.0
1.2
1.5
1.6
1.8
2.0
2.2
2.4
2.6
2.9
3.1
3.3
3.5
3.7
3.9
4.1
4.4
4.6
4.8
5.0
5.2
74
TEMPERATURE CORRECTIONS FOR THE LACTOMETER
[Vol. XIX, Part I,
TABLE II—contd.
Table for correcting Lactometer reading to 60º F.
Temperature in degrees
Farenheit
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
To be added to the L.R.
Percentage of fat observed
3
4
5
6
7
8
Corrections to correct L.R. to 60ºF.
4.4
4.6
4.8
4.9
5.1
5.3
5.5
5.7
5.9
6.1
6.4
6.6
6.8
7.0
7.2
7.4
7.6
7.8
8.0
8.3
8.5
8.7
9.0
9.2
9.4
4.6
4.8
4.9
5.1
5.3
5.5
5.7
6.0
6.2
6.4
6.6
6.9
7.1
7.3
7.5
7.7
7.9
8.2
8.4
8.6
8.9
9.1
9.3
9.6
9.8
5.1
5.2
5.4
5.6
5.8
6.0
6.2
6.4
6.6
6.9
7.1
7.3
7.5
7.7
7.9
8.2
8.4
8.6
8.8
9.0
9.3
9.5
9.7
10.0
10.2
5.2
5.4
5.6
5.8
6.0
6.2
6.5
6.7
6.9
7.2
7.4
7.7
7.9
8.2
8.4
8.6
8.8
9.0
9.2
9.5
9.7
9.9
10.1
10.4
10.6
5.3
5.6
5.8
6.0
6.2
6.4
6.7
6.9
7.1
7.4
7.6
7.9
8.3
8.4
8.6
8.8
8.0
9.2
9.5
9.7
9.9
10.1
10.3
10.6
10.8
5.4
5.7
5.9
6.1
6.3
6.6
6.8
7.1
7.3
7.6
7.8
8.1
8.3
8.6
8.8
9.1
9.3
9.5
9.8
10.0
10.2
10.3
10.7
11.0
11.2
March, 1949] ZAL, R. KOTHAVALLA, C. P. ANANTAKRISHNAN AND T. M. PAUL 75
Lactometer readings were also taken with each increase of 5ºF. temperature,
and the difference of the lactometer reading from that at 60ºF. was then plotted
against the temperature. The points were found to be on the same curve as with
an interval of 10°F. Cow and buffalo milks of the same fat percentage were studied
and were found to behave similarly with regard to the change of lactometer reading
with a rise in temperature. Further, cow and buffalo milks were mixed in various
proportions and the change in lactometer reading in relation to temperature studied,
There again the samples were found to behave quite normally with regard to the
correction factors. Milk samples having various acidities ranging from 0.11 to
0.20 per cent lactic acid were also studied in a similar way. It was found that
acidity had no effect on the lactometer readings and their corrections.
Fig. 1.
VERIFICATION OF THE CORRECTION TABLE
The Correction Table was verified with cow and buffalo milk-samples selected
at random. The correct lactometer reading at 60ºF., one reading between 50ºF.
and 60ºF., and 2 or 3 readings at temperatures between 60ºF. and 110ºF. were taken
for each sample. The actual difference between the lactometer readings at 60ºF.
and other temperatures were thus determined and compared with the readings
March. 1949] ZAL, R. KOTHAVALLA, C. P: ANANTA KRISHNAN AND T. M. PAUL 77
SUMMARY
(a) A new table (Zal-Krishnan) has been prepared for the correction factors
of lactometer readings with various temperatures and fat percentages of the milk
of Indian cows and buffaloes.
(b) The table provides correction factors for a temperature range of from 50°F.
to 110ºF.
(c) For the accurate determination of the specific gravity of milk by this.
method it is essential that the fat percentage should be known.
REFERENCES
British Standard Specification, No. 734, (1937)
Hutchinson, R.C. (1940) J. Aus. Inst. Agri. Sci.; 6. 205
Richmond, H.D. (1899). Dairy Chemistry 1st Edition
Vieth, P. (1885). Analyst 10.63
Wright, H. (1913). f. Soc. Chem. Ind. 32. 777
PLATE IV]
[Indian
J. Vet. Sci. Vol.-XIX, Part I
FIG. 1. Collection of semen from cock
FIG. 2. Inseminating a hen
FIG. 3. Semen of cock
SEM EN STUDIES AND ARTIFICIAL INSEMINATION IN
POULTRY
By D. P. MUKHERJEE and P. BHATTACHARYA, Indian Veterinary Research Institute,
Izatnagar
(Received for Publication on 17 July 1948)
(With plate IV and one text figure)
A RTIFICIAL insemination in poultry was first attempted by Ivanoff [1913].
Since his pioneer work various techniques for collection of semen from cocks
and for inseminating the hens have been tried by several workers abroad. However,
artificial insemination in poultry has not assumed the same importance that it has in
large farm animals. The reasons are that most of the Western countries have
already reached a very high and uniform standard of excellence in poultry and
production costs in poultry are nomimal as compared to those in large farm animals.
Furthermore, there is no great scarcity of high quality cocks for breeding purposes.
Also fertile pedigree eggs can be had easily. The life-cycle in these animals is very
short and huge flocks can be developed in about a couple of years.
In India the conditions are different. Poultry husbandry is yet in its infancy.
The size of birds is small and their performances poor. Good birds are rare. By
the introduction of artificial insemination, a large number of hens can be bred from
a few outstanding cocks. Also, it will remove the difficulty of physical incompa-
tibility encountered in mating small sized hens with large sized cocks. To carry
out a successful programme of breed improvement by grading and other breeding
practices information regarding the characteristics of cock semen is needed.
The present experiment was undertaken to determine the characteristics of
semen of desi cocks and exotic birds (White Leghorns) reared in India.
MATERIAL
The experimental material consisted of three one year old White Leghorns,
an equal number of desi birds of the same age, and 13 laying hens. Of the 13 hens
six were White Leghorns and the remaining Rhode Island Reds. The birds were
obtained from the poultry farm, Indian Veterinary Research Institute, Izatnagar.
The hens were housed in a shed 14 fit, 3 in. × 11 ft. opening on one side into
a run 18 ft. 6 in. × 14 ft. The cocks were kept confined in separate cages
1 ft. 7½ in. × 1 ft. 4½ in. × 2 ft 5 in. throughout the experimental period, except at the
time of semen collection. Care was taken that each cock received sufficient
sunlight. The birds were kept on a balanced ration throughout the experimental
period.
METHOD
Collection of semen from cocks and insemination of hens were made according
to the method of Burrows and Quinn [1935]. The semen is collected by massaging
the soft part of the abdomen below the pelvic bones of a cock as shown in Plate IV.
fig. 1 and for inseminating the oviductal opening of the hen is first exposed by
79
R
80
SEMEN STUDIES AND ARTIFICIAL INSEMINATION IN POULTRY [Vol. XIX, Part I,
exerting digital pressure on the abdomen and the semen is deposited in the oviduct
as shown in Plate I, fig. 3.
Semen samples were collected from each cock every Monday and Thursday.
The Monday collection was used for the study of semen characteristics and the other
sample was used for insemination. Twentyfive samples from each cock were studied
for the following characteristics (i) colour and consistency, (ii) volume, (iii) pH,
(iv) initial motility of spermatozoa, (v) sperm concentration per c.c., (vi) total number
of spermatozoa and (vii) percentage of abnormal spermatozoa.
Colour, consistency, volume and motility were observed immediately after
collection. Volume was measured to the nearest 1/100 c.c. and the degree of motility
was scored in terms of criterian recommended by Erb, Andrews and Hilton [1942].
pH was determined by B.D.H. Capillator within 10 minutes after collection. Sperm
density was determined by the haemacytometer method in terms of millions per
c.c. [Macirone and Walton, 1938]. To determine the percentage of abnormal sper-
matozoa the following methods of fixation and staining were adopted. A very thin
film of semen was made by adding a drop of semen to normal physiological saline
solution on a clean slide. The film was then fixed in the vapour of 2 per cent osmic
acid for about 10 to 15 minutes and stained with 0.1 per cent methylviolet for 15 to 20
minutes. One hundred spermatozoa were examined at random with the aid of
an oil immersion lens and abnormal spermatozoa were noted. The semi-diagramatic
camera lucida drawings of normal and various abnormal spermatozoa found during
the course of the experiment are given in Fig. 1.
Fig. 1. Normal and abnormal spermatozoa of fowl (Magnification × 840)
March, 1949]
D.
P.
MUKHERJEE
AND
P.
BHATTACHARYA
81
Each hen was inseminated once a week with 0.3 c.c. of diluted semen (1 part
of semen and 2 parts of Ringer's solution) by depositing it into the exposed orifice
of oviduct with the help of a micropipette (Plate I, fig. 3).
RESULTS
Table I shows the various physical characteristics of semen produced by the
cocks. It will be seen from this Table that in desi birds colour and consistency
of semen varied from very thin milky to thick milky whereas in White Leghorns
variations were from milky to very thick milky. The mean volume in desi birds
varied from 0.182 ±0.011 to 0.335±0.018 and in White Leghorns from 0.304±0.012
to 0.43±0.026. The mean pH in desi birds varied from 6.6±0.05 to 6.8±0.03
and in White Leghorns 6.4±0.46 to 6.8±0.13. The most common initial motility
of spermotozoa of the two breeds was +++++. The mean sperm concentration
in desi birds ranged from 1635±253 to 3287±240 and in White Leghorns from 2891±
347 to 3852±185 millions per c.c. The mean total number of spermatozoa in
desi varied from 491±77 to 1012±104, and in White Leghorns from 1191±92
to 1266±199 millions. The mean percentage of abnormal spermatozoa in desi
birds varied from 3.2±0.172 to 4.08±0.288 whereas in White Leghorns from 3.68±
0.31 to 3.8±0.29.
On the whole the quality of semen of White Leghorns as judged by colour and
consistency, volume, sperm concentration and the total number of spermatozoa,
was superior to that of the desi.
The data of the various attributes of semen of the two breeds have been statisti-
cally analyzed and the results are presented in Table II. It will be seen from this
Table that highly significant variations were found in volume and the total number
of spermatozoa per collection in the two breeds. Significant variation had been
noticed in the sperm concentration of the two breeds. There was, however, no
significant variation in pH, initial motility and the percentage of abnormal
spermatozoa.
Fertilizing quality of the semen produced by the experimental cocks is shown
in Table III. This Table also shows the plan of artificial breeding. This plan
was followed throughout the experiment with a view to minimise the effect of breed
difference in hens, if any, on fertility. The percentage of fertility in birds inseminated
with semen of desi cocks was 82.21 and in those inseminated with White Leghorn
semen 88.73.
DISCUSSION
The volume of semen obtained per collection in this study was comparatively
smaller than that reported by Lambert and Mackenzie [1940], but it was similar
to that obtained by Martinaz [1939]. It may be mentioned here that considerable
variation exists in the amount of semen produced by different cocks and even in
the same bird at different times, Hutt [1929]. It would be necessary to undertake
an extensive study to determine definitely, whether the volume of semen produced
by cocks in India was really smaller than the birds reported by Lambert and Macken-
zie [1940], pH and sperm concentration of semen were within their respective ranges
R 2
82 SEMEN STUDIES AND ARTIFICIAL INSEMINATION IN POULTRY [Vol. XIX, Part I,
TABLE I
Characteristics of semen produced by desi and White Leghorn cocks
Cock No. and their
114 Desi . . .
158 Desi . . .
2320 Desi . . .
667 White Leghorn .
676 White Leghorn .
664 White Leghorn .
No. of
samples
studied
25
25
25
25
25
25
Colour and consistency
Range
Thin milky to thick milky
Very thin milky to thick
milky
Thin milky to thick milky
Very thin milky to very
thick milky
Thin milky to thick milky
Very thin milky to very
thick milky
Most
common
Thick
milky
Very
thin
milky
milky
Very
thick
milky
Milky
Very
thick
milky
Volume (in c.c.)
Min.
0.14
0.12
0.11
0.2
0.23
0.13
Max.
0.5
0.51
0.35
0.5
0.7
0.9
Mean
0.335
±0.018
0.226
±0.019
0.182
±0.011
0.304
±0.012
0.43
±0.026
0.378
±0.376
pH
Min.
6.6
6.6
6.2
5.7
6.6
6.6
Max.
7.0
7.2
7.0
7.4
7.0
7.0
Mean
6.8
±0.03
6.8
±0.02
6.6
±0.05
6.8
±0.13
6.7
±0.02
6.4
±0.46
Initial motility
Min.
+ + + +
+ +
++
+++
+++
+
Max.
+ + + + +
+ + + + +
+++++
+++++
+++++
+++++
Most
common
+++++
+++ to
+++++
+++++
+++++
+++++
+++++
March, 1949]
D.
P.
MUKHERJEE
AND
P.
BHATTACHARYA
83
TABLE I—contd.
Characteristics of semen produced by desi and White Leghorn cocks
Cock No. and their
breeds
114 Desi . . .
158 Desi . . .
2320 Desi . . .
667 White Leghorn
676 White Leghorn
664 White Leghorn
No. of
samples
stidued
25
25
25
25
25
25
Colour and consistency
Range
Thin milky to thick milky
Very thin milky to thick
milky
Thin milky to thick milky
Very thin milky to very
thick milky
Thin milky to thick milky
Very thin milky to very
thick milky
Most
common
Thick
milky
Very
thin
milky
Milky
Very
thick
milky
Milky
Very
thick
milky
No. of sperms per c.c.
Min.
1280
152
1040
640
1520
44
Max.
4500
3920
5360
5200
5120
5560
Mean
8140
±107
1635
±253
3287
±240
3852
±185
3024
±190
2891
±347
Total No. of sperms
(in millions)
Min.
115.2
12
208
160
560
5.72
Max.
2240
840
1126.4
2400
1888
3744
Mean
1012
±104
491
±77
817
±68
1191
±92
1256
±232
1266
±199
Percentage of abnormal sper-
Min.
2
2
1
0
0
0
Max.
6
6
6
6
7
7
Mean
4.08
±0.288
3-84
±0-214
3.2
±0.172
3.8
±0.29
3.72
±0.254
3.65
±0.31
84
SEMEN STUDIES AND ARTIFICIAL INSEMINATION IN POULTRY [Vol. XIX, Part I,
TABLE II
Significance in semen characteristics of the two breeds
Semen characteristics
Volume in c.c . . . . .
pH
.
.
.
.
.
.
.
Initial motility . . . . .
No. of spermatozoa per c.c. (in millions)
Total number of spermatozoa per collection
Percentage of abnormal spermatozoa
Mean of
White
Leghorn
0.37
6.686
4.7
3256
1237
3.62
Mean of
Desi
breed
0.26
6.833
4.57
2706
773
3.72
Difference
of the
two means
0.11
0.147
0.13
550
464
0.10
Standard
error of
the mean
0.025
0.1634
0.152
211
38
0.25
t.value
4.40**
1.11
0.85
2.606*
12.2**
0.4
TABLE III
Fertilizing quality of semen produced by White Leghorn and desi cocks
Cock No. and breed
664 White Leghorn . . .
667 White Leghorn . . .
676 White Leghorn . . .
114 Desi . . . . .
158 Desi . . . . .
2320 Desi . . . . .
Mated to hen No.
and breed
342 (R. I)
424 (W. L)
742 (R. I)
709 (W. L)
328 (R. I)
340 (R. I)
422 (W. L)
381 (W. L)
341
603 (W. L)
607 (R. I)
358 (W. L)
530 (R. I)
Total No.
of eggs
laid
47
42
71
59
116
40
Total No.
of fertile
eggs
42
38
62
52
97
30
Percentage
of fertility
89.3
85.7
87.2
88.14
83.5
75.0
Average
percentage
of fertility
88.73
82.21
W. L—White Leghorn
R. I—Rhode Island Red
March, 1949] D. P. MUKHERJEE AND P. BHATTAOHARYA 85
as given by Lambert and Mackenzie [1940], As regards the percentage of abnormal
spermatozoa there was no wide variation between the two breeds. The mean
percentage of abnormal spermatozoa did not exceed more than five per cent. Samp-
son and Warren [1939] also found that in males of proved normal fertility the
abnormalities of sperm were up to five per cent.
Burrows and Quinn [1937] obtained 90 per cent fertility in fowls by inseminating
one hen per week with 0.1 c.c. of good quality semen. Jeffrey [1941] reported 82
per cent fertility in hens by inseminating once a week with the same amount. It
seems, therefore, that percentage of fertility may vary from 82 to 90 per cent in fowls
by one insemination a week with 0.1 c.c. of good quality of semen. The percentage
of fertility obtained for individual birds as well as for the two breeds were almost
the same as reported by the above mentioned workers. The difference in percentages
of fertility as found in desi and White Leghorn cocks may not be due to the difference
in the semen quality of the two breeds.
SUMMARY
Various characteristics of semen of White Leghorns and desi birds have
been studied.
Significant variation was found in volume, total number of spermatozoa
and concentration of spermatozoa in the two breeds—White Leghorn being superior
to desi birds.
No significant variation was found in pH, initial motility and percentage
of abnormal spermatozoa.
The percentage of fertile eggs laid by birds inseminated with semen from
desi cocks was 82.21 against 88.73 in those inseminated with White Leghorn's semen.
REFERENCES
Burrows, W.H., and Quinn, J.P. (1935). Poult. Sci. 14, 251
Burrows, W. H., and Quinn, J.P. (1937). Ibid 16, 19
Erb, R.E., Andrews, F.N. & Hilton, J.H. (1942). J. Dairy Sci. 25, 206
Hutt, F.B., (1929). Proc. Roy. Soc. Edin. 49, 102
Ivanoff, E., (1913). Comp. Rec. Bio. 75, 371
Jeffrey, F.P., (1941). Hints to Poultrymen N. J. Agric. Exp. Sta. 28, 2
Lambert, W.V., & Mackenzie, F.F. (1940). Circ. U. S. Dep. Agric. 567, 36
Macirone, C., & Walton, A. (1938). J. Agric. Sci. 28, 122
Martinez, G.M., (1939) Rev. Med. Vet. (Bogota) 9, 76, 347
Sampson, F.R., & Warren, D.C., (1939). Poult. Sci. 18, 301
ABSTRACTS
COCCIDIOSIS OF POULTRY. ' SULPHA' DRUGS OFFER NEW
HOPE OF CONTROL
Fischel, W.G. (1946). Newzealand J. Agri. 73, (6), 515-517
T HE author has found Sulphamezathine to be very useful for the treatment
and control of every type of coccidia affecting the poultry. Both forms of
administration, i.e., in drinking water and with the feed are equally effective but
the former appears to be less wasteful and ensures the intake even if the appetite
is impaired by the inflammatory condition of the intestines characteristic of coc-
cidiosis. Saturated solution of the drug is, for example, prepared by dissolving
0.5 gm. (or 8 grains) in hot water by constant stirring. For four-day treatment of
hundred chicks of varying ages the proportionate requirement of the drug and water
is as follows:
Age 1-2 weeks . . . . . .
„ 2-3 „ . . . . . .
„ 3-4 „ . . . . . .
„ 4-5 „ . . . . . .
„ 5-6 „ . . . . . .
10 gm. in 2½ gallons
12 gm. „ 3 „
18 gm. „ 4½ „
24 gm. „ 6 „
34 gm. „ 8½ „
Fresh medicated water should be prepared daily in order to maintain the full
strength and should be served in earthenware or glass vessel.
When the drug is given in feed it is recommended to continue the treatment
for one week. The drug in the powder form is mixed with the mash at the rate of
½ ounce to every 10 pound of dry mash.
Birds recovering after treatment become immune to infection with the same
type of coccidia. (H.S.)
A Virus causing Abnormal Milk in Cattle
Baker, J. A. and Little, R. B. (1946). Proc. Soc. Exp. Biol. and Med., 63 (2), 406-407
T HE authors have reported the occurrence of an infection, in dairy cows near Prin-
ceton, N. J., characterised by fever and the milk containing flakes composed
of polynuclear and mononuclear cells. Most of the cases occurred in the later part
of May and in June 1946. Guinea pigs, inoculated intraperitoneally with milk
from natural cases, showed thermal reaction and recovered; those killed during
the febrile period revealed haemorrhages in the lungs, focal necrosis of the liver and
slight enlargement of the mesenteric lymph nodes. Blood from the first and the
sixth guinea pig passages was infective to calves and lactating cows. The agent
was transferred to rabbits and mice by the intravenous and intraperitoneal routes
respectively. The causal factor could also be cultivated on the chorioallantoic
87
S
88
ABSTRACTS
[Vol. XIX, Part I,
membrane of the develop g chick. The authors demonstrated the presence of the
agent after ten serial egg passages. No pathological change of the membrane was
noticed during the course of such passages.
Attempts to demonstrate the agent microscopically and culturally failed. In
view of the above findings it was considered that the infection was due to a virus.
(C.S.)
THE AMOUNT OF DDT FOUND IN THE MILK OF COWS FOLL-
OWING SPRAYING
Howell, D. E., Cave, H. W., Heller, V. G. and Gross, W. G. (1947)
J. Dairy Sci. 30, 717
I N this article the authors have recorded their observations on the amount and
toxicity of DDT found in the milk of cows following the recommended and
excessive spraying with the drug for the period beginning from July 15 to August 30.
Four equal lots, each comprising of two Jerseys and two Holstein dairy cows, were
employed in the experiment. The first lot was sprayed daily with 2 quarts of 5
per cent water suspensible DDT spray per animal and the second with a similar
quantity of 5 per cent emulsion for the first four days and 1 per cent for the subse-
quent period of the experiment to prevent tissue damage. The third and the last
lots were sprayed individually on the same day every other week, the former with
2 quarts of 0.25 per cent water suspensible powder and the latter with 2 quarts of
0.25 per cent emulsion. In addition to these animals one single cow was sprayed
and sampled daily with 2 quarts of 5 per cent water suspensible DDT from August 10
to August 30, to provide more comprehensive data of the elimination of DDT through
the milk. It was found that milk samples collected from the experimental cows
three and ten days after spraying contained no DDT; but all samples collected on the
seventeenth day after spraying was started were positive for qualitative tests.
The amount of DDT found in the milk as a result of quantitative tests ranged from
slight traces to 33.6 parts per million. The milk of Jerseys generally contained
more DDT than those of Holsteins. It was concluded that all animals tested ex-
creted some DDT in the milk and those sprayed with excessive amounts continued
to eliminate DDT until the end of their lactation period, 119 and 126 days after
the last spraying but none after freshening. Biological tests to determine the toxi-
city of the milk conducted on mice, mosquito larvae and flies proved to be negative.
(T.A.)
A TECHNIQUE FOR THE ISOLATION OF COAGULASE-PRODUC-
ING STAPHYLOCOCCI FROM MILK IN BOVINE MASTITIS
Delia M. Velilla, Faber, M. S. J. E., Jr., Ph. D., and Pelczar, M. J., Jr., Ph. D.,
College Park, Maryland (1947). Amer. J. vet. Res. 8, 275
T HE authors have made a comparative study of Difco phenol red, mannitol, salt
agar (PRMS), dehydrated (experimental); and Difco Staphylococcus Medium
110 (SM 110), dehydrated (experimental) in isolating pathogenic strains of Staphy-
lococci from milk, taking mainly coagulase-production as the criterion of patho-
genicity. Composition of the media is described. Plating was done by spreading