NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
8
Now, basing the calculation on this fact, viz., that 1 C. Cm
.
of
serum
can
neutralise from 0·6 to 0·7 mgrms. of cobra venom, and on the first two assumptions
stated above, we arrive at the conclusion that instead of 15 C. Cm. of serum, a
dose of from 22 to 25 C. Cm. would have to be given to prevent death from
the bite of a full-sized cobra.
As we have already stated, one of the assumptions on which the above cal-
culation is founded is, that the minimum lethal dose of cobra venom for a man is
as much as 31 milligrammes. This assumption is based partly on the fact,
experimentally shown by Calmette 15 and other observers, that for such animals as
the guinea-pig, the rabbit, the dog, the monkey and the ass, the larger the animal
the greater is the amount of cobra venom, weight for weight, required to cause
death. This rule, however, does not hold good for all species of animals. Thus
Myers16 has shown that the minimum lethal dose of cobra poison for a mouse of
15 grammes in weight is 0•012 mgrms. If the rat were as susceptible to this
poison as is the mouse, the lethal dose for a rat of 120 grammes in weight would
be 0 • 096 mgrms. We have, however, seen above that the minimal lethal dose for a
rat of this size is only 0.04 mgrms., namely, that the rat is at least twice as
susceptible to cobra venom as is the mouse.
In view of this fact it would seem expedient, in estimating the dose of anti-
venomous serum to be given in a case of cobra bite, to base our calculations on
the assumption that man is at least as susceptible as the most susceptible animal
with which experiments have been made, viz., the rat. Assuming then that man
is as susceptible as the rat, it is evident that the minimum lethal dose for a man
of 60 kilos weight would be about 20 mgrms., and the maximum dose which he may
naturally be able to resist, say 19 mgrms. We can therefore calculate that if a cobra
had injected the maximum amount of venom possible, viz., 45 mgrms. (an assump- -
tion which it would be necessary to make in every case of snake bite), the
quantity of serum required to merely save the life of any one receiving this injec- -
tion would be the amount which was capable of neutralising at least 45–19 mgrms.
=26 mgrms. This amount of fresh serum,—namely, serum, 1C. Cm. of which was
able to neutralise about 0·7 mgrms. of cobra venom,—would be about 37 C. Cm.
It is interesting in this connection to point out that Calmette 17 himself has arrived
at the conclusion that the minimum lethal dose of cobra venom for a man is only
about 10 mgrms. Working on this latter hypothesis, it is evident that it would
require about 50 C. Cm. of serum to save a patient who had received the maxi-
mum quantity of venom which a cobra can inject.
Our contention that 15 C. Cm. of serum is quite an inadequate dose for the
treatment of a case of cobra bite, receives corroboration from a consideration of
the accidental case which occurred in this laboratory a short time ago. 1 8
*
The only treatment employed in this case was the subcutaneous injection of
* Vide foot-note on page 1.
9
anti-venomous serum. Immediately after the accident 18 C. Cm. of old serum were
injected. This was the serum obtained from the Bombay Natural History Society,
the neutralising power of which was tested in the experiments detailed in series
No. IV of the protocols. From a reference to the protocols it will be seen that
1 C. Cm. of this serum was able to neutralise 0·29 mgrm. of pure cobra venom.
It follows, then, that 18 C. Cm. of such serum was equivalent to 75 C. Cm.
of fresh serum, that is, of serum 1 C. Cm. of which was capable of neutralising
0 ·7 mgrm. of venom. Our patient, therefore, received as a preliminary dose a
quantity of serum equivalent to 7·5 C. Cm. of a prefectly fresh serum. In spite
of this injection, well-marked general symptoms referable to the central nervous
system set in about 21/2 to 3 hours after the accident. The case in all probability
would have had a fatal ending had not a second injection of fresh serum been
given before the symptoms had progressed too far.
Now in this case the poison from one gland only was injected. We can there-
fore conclude that 15 C. Cm. of fresh serum would have been quite inadequate
to have prevented the onset of symptoms of intoxication and probably would
not have prevented death had the patient received the quantity of poison con-
tained in both glands.
Shortly after the onset of symptoms 10 C. Cm. of comparatively fresh
serum were injected. This was serum got from Messrs. Phillips & Co., vide
series No. III in protocols. We have seen that 1 C. Cm. of this serum was capable
of neutralising 0·61 mgrm. of cobra poison. The dose which was injected was
therefore, equivalent to 8 . 7 C. Cm. of perfectly fresh serum, such as was used in
the experiments detailed in series No. II of the protocols. Our patient, therefore,
received in all a quantity of serum equivalent to 16 C. Cm. of perfectly fresh
material.
All symptoms in this case, in which the bite was inflicted by only one fang,
soon passed off after the second injection of serum. Since, however, the second dose
was given after some of the poison had already joined on to the central nervous
system, it is for à priori reasons necessary to conclude that a smaller dose
would have sufficed, if the whole quantity had been injected before the onset of
any symptoms. On the other hand, it must be remembered that the cobra which
inflicted this bite had been in captivity for some months and would not conse-
quently yield as much poison as an ordinary snake in nature would do. For it is
an observation of common occurrence in this laboratory that a cobra newly caught
will yield from 20 to 30 large drops of poison, while after he has been a captive
for some time this quantity will have diminished to from 6 to 10 drops and in
time to nil.
From what we have stated above it is evident that the question of the dose
of serum to be injected in cases of cobra bite turns upon factors which cannot be
directly experimentally determined— viz.:—(I) upon the amount of poison which
the snake has injected; and (2), upon the amount of cobra venom which an
average man can survive.
In view of the fact, however, that in the treatment of any case of cobra bite
we must always estimate the dose of antivenene to meet the possibility of the
snake having injected the maximum quantity possible, i.e., about 45 mgrms., and
in view of the fact that man may be as susceptible, weight for weight, as the rat
or perhaps more susceptible, it seems to us from the considerations put forward
above that a dose of from 30 to 35 C. Cm. of fresh serum, or the equivalent of
this, should be given in every case of cobra bite. A larger dose would, of course, be
necessary if symptoms had set in before the treatment was begun. At any rate
the history of this case shows that a dose of about 15 C. Cm. would be quite
inadequate in most cases of cobra bite.
We may now pass on, in conclusion, to consider briefly the question of the
deterioration which anti-venomous serum undergoes by keeping in India. The
data bearing on this subject are contained in detail in the protocols, series No. II
to No. VIII inclusive. These data may be briefly summarised in tabular form as
follows:—
Series in
Protocols.
Age of serum. Length of time
in India.
Where kept in
India.
Neutralising
power.
REMARKS.
No. II
•
2 months
•
1 month
•
Bombay
•
1 C. Cm.
neutralised
0
∙ 7 3 m g r m .
This serum may be re
garded as perfectly
fresh serum.
No. III
•
_
7 months
3 months
•
Bombay
•
1 C. Cm.
neutralised
0
∙ 6 1 m g r m .
No. IV
• Over 3 years About 3 years Bombay
•
1 C. Cm.
neutralised
0
∙ 2 9 m g r m .
No. V
•
Over 3 years About 3 years Nasik and
Bombay.
1 C. Cm.
neutralised
0
∙46 mgrm.
It is uncertain how long
this sample had been
in Bombay and how
long in Nasik.
No. VI
•
4 years
•
1¼ years
Indore
•
1 C. Cm.
neutraiised
0
∙ 1 8 m g r m .
No. VII
•
5 years
•
Over 4 years Agra
• •
1 C. Cm.
failed
to neutralise
0∙14 mgrm.
No. VIII
•
4 years
•
2¼ years
•
Bombay, and
Berar.
1 C. Cm. failed
to neutralise
0
∙ 1 8 m g r m .
Bombay 6 months, Be
rar 1¾ years.
The protective power ascribed by M. Calmette to all samples of sera sent
out from Lille is 20,000 units per 10 C. Cm. We may, therefore, assume that all
brews when fresh possess practically the same neutralising power (vide foot note,
page 4). A study of the above table shows that a progressive deterioration takes
place from keeping the serum in India. Thus it will be noticed, on the one hand,
that while the serum which was seven months old and had been in India for only
three months (No. III) already showed a slight diminution in its neutralising power;
on the other hand, the sera which had been kept for some years in the Berars
(Hingoli and Ellichpur), i.e., No. VIII, and in Agra, i.e., No. VII, had practically
lost all neutralising power, and the sera which had been stored at Indore, Bombay,
and Nasik had deteriorated to a considerable extent, but had not completely lost
all neutralising power.
Let us consider for a moment the climatic conditions as regards tempera
ture which prevail at these different places.
In the cold season Agra and the Berars have a comparatively low temperature;
but for three or four months of the year the heat in these districts is excessive,
the maximum temperature in the shade being seldom below 105° F. and often
reaching 110° F. and over.
Indore also has a severe hot weather and a comparatively cool cold season,
a similar climate in fact to that of Berar, although, perhaps, the maximum tem
perature does not reach so high as in the other two cases.
The greater neutralising power of the serum which had been kept at Indore
compared with the Berar and Agra samples, can be accounted for by the fact
that the former sample had been subjected to this great heat for only one hot
season, while the Berar and Agra sera had been stored in these districts during
two and four hot weathers, respectively.
The results obtained with sera Nos. IV and V are especially interesting.
Both these sera were of the same age and were imported to Bombay at the same
time. One sample, viz., No. V, had been stored for a considerable time at Nasik
after Bombay. Now the temperature of Nasik during the cool season of the
year is much lower than that of Bombay. On the other hand, during the hot
months, March to May inclusive, the maximum shade temperature of Nasik is
only slightly lower than that of Bombay, while the minimum temperature is much
lower. On the whole, therefore, we may take it that the serum which had been
kept at Nasik had not been subjected to nearly such a high mean temperature
during the year as had that serum which had been stored in Bombay. In conse
quence, the neutralising power of the former was more than a half greater than the
neutralising power of the latter.*
We may conclude then from these data that anti-venomous serum under
goes a progressive and fairly rapid deterioration when stored in hot climates, and
that this deterioration is greater and more rapid the higher the mean tempera
ture to which it is subjected.
* Experiments are at present in progress in this Laboratory to ascertain, if possible, the causes of this
difference,— such as the effect of heating on the poison as regards the amount of serum required to neutra
lise a given quantity before and after heating, etc.
The practical bearings of the results of these observations are so patent as
to require no further discussion.
Protocols.
SERIES No. 1.—Experiments to determine the minimum lethal dose of pure
cobra venom for a rat of about 118 grammes.
The poison used was carefully dried pure fresh cobra venom. It was
unheated. A 0.1 per cent. solution in sterile normal saline solution was made.
Ten-fold and hundred-fold dilutions of this original solution were used when
necessary. The weights refer to the original dried venom.
All rats were carefully selected about 118 grammes weight. The injections
were made subcutaneously in the inner side of the thigh.
A n i m a l .
Amount of dried venom in
Milligrammes.
Result
Rat 1 . .
0 . 1
Died within 2 hours.
Rat 2
.
.
0 . 0 9
Died within 2 hours.
Rat 3 . .
0.08
Died within 2 hours.
Rat 4
. .
0 . 0 7
Died within 3 hours.
Rat 5
. .
0 . 0 6
Died within 3 hours.
Rat 6
. .
0.05
Died within 3 hours.
Rat 7
. .
0.05
Died within 3 hours.
Rat 8
. .
0.045
Very ill for 24 hours; died in 4 days.
Rat 9
. .
0 . 0 4
Died in 3¼ hours.
Rat 10
. .
0.04
Died in 2¼ hours.
Rat 11
. .
0.035
Ill for IS hours ; recovered.
Rat 12
. .
0 . 0 3 5
Ill for 6 hours ; recovered.
Rat 13
. .
0.03
Slightly ill for 3 hours; recovered.
Rat 14
.
.
0.03
No symptoms.
Rat 15
. .
0 . 0 2 5
No symptoms.
Rat 16
. .
0.02
Slight symptoms; recovered.
Rat 17
. .
0 . 0 1
No symptoms.
Rat 18
. .
0.005
No symptoms.
From the above table it appears, then, that 0.04 mgrm. is a certain lethal
dose, and that 0.035 mgrm. is a dose which a rat of this size can survive, i.e .,
a maximum non-lethal dose.
In the series of experiments No. II to No. VIII, detailed hereafter, ten lethal
doses,—namely, mgrm.—were mixed in vitro with varying amounts of sera of
different ages and which had been kept under different conditions of temperature.
The mixtures were allowed to stand at laboratory temperature (about 25° C.)
for at least half an hour, and were then injected subcutaneously in the inner
13
side of the thigh. Carefully selected rats of about 118 grammes weight were
used in all cases. In calculating the amount of venom which the serum had
been able to neutralise or had failed to neutralise, the maximum non-lethal dose
—namely, 0.035 mgrm.—was deducted in all cases.
These series are as follow:—
SERIES NO. II.—Experiments to ascertain the amount of venom which 1 C. Cm.
of fresh serum newly imported was capable of neutralising.
The serum used in this series of experiments was received from Lille in
October, 1900. It was dated 17th September 1900. The experiments were
completed between the 10th November and 5th December.
A n i m a l .
Amount of dried
venom in
Milligrammes.
Amount of serum
in C. Cm.
Result.
Rat 1
. . .
0.4
0.15
Died in 5 hours.
Rat 2 . . .
0.4
0.2
Died in 10¾ hours.
Rat 3 . . .
0.4
0.2
Died in 7½ hours.
Rat 4 . . .
0 . 4
0.2
Died in 2¾ hours.
Rat 5 . . .
0.4
0.2
Died within 48 hours.
Rat 6 . . .
0.4
0.25
Died in 2¾ hours.
Rat 7 . . .
0.4
0.25
Died within 17 hours.
Rat 8 . . .
0.4
0 . 2 5 Died within 5 hours.
Rat 9 . . .
0.4
0.3
Very ill for 48 hours; recovered.
Rat 10 .
.
0 . 4
0.3
Died in 5 hours.
Rat 11 . . .
0 . 4
0.3
Died in 2¾ hours.
Rat 12 . . .
0.4
0.3
Died within 5 days.
Rat 13 . . .
0.4
0.35
Died within 48 hours.
Rat 14 . . .
0.4
0.35
Died within 48 hours.
Rat 15 . . .
0 . 4
0.35
Died in 17 hours.
Rat 16 . . .
0.4
0.4
Died within 40 hours.
Rat 17 . . .
0.4
0.4
Ill for 5 days; recovered.
Rat 18 .
.
.
0.4
0 . 4
Died within 48 hours.
Rat 19 . . .
0.4
0.45
Died within 3 days.
Rat 20 . . .
0.4
0.45
Died after 8 days.
Rat 21 . .
0.4
0.5
No symptoms.
Rat 22 . . .
0.4
0.5
Ill for 2 days; recovered.
Rat 23 . . .
0.4
0 . 6
Ill for 2 days; recovered.
Rat 24 .
.
.
0.4
0 . 7
No symptoms.
From the above series we can conclude that 0.45 C. Cm. of this serum
failed to neutralise with certainty 0.4 — 0.035 mgrm.=0.365 mgrm.; while 0.5
C. Cm. could neutralise this amount. In other words, 1 C. Cm. was able to
neutralise 0.73 mgrm.
14
SERIES No. 111.—Experiments to ascertain the amount of venom which
1 C. Cm. of comparatively fresh serum was capable of neutralising.
The serum used in this series was dated 8th May 1900. It was purchased
from Messrs. Phillips & Co., Chemists, Bombay, who had received it from
England about the end of August. The experiments were completed between
the 5th and 12th December. The serum had, therefore, been in Bombay during
one of the hottest months of the year, viz ., October.
A n i m a l .
Amount of dried
venom in
Milligrammes.
Amount of serum
in C. Cm.
Result.
Rat 1 . . .
0.4
0.2
Died in 2 hours.
Rat 2 . . .
0.4
0.3
Died in 2 hours.
Rat 3. .
0.4
0.4
Died within 42 hours.
Rat 4 . . .
0.4
0.5
Died within 42 hours.
Rat 5 . . .
0
•
4
0.5
Died within 46 hours.
Rat 6 . .
0.4
0.6
Ill for one day; recovered.
Rat 7 . . .
0.4
0.6
No symptoms.
Rat 8 . . .
0.4
0. 7
No symptoms.
Rat 9 . .
0.4
0.7
No symptoms.
Rat 10
. . .
0
.
4
0.8
No symptoms.
From the above series we can conclude that 0 .5 C. Cm. of this serum failed
to neutralise 0.4
—
0.035 mgrm.=0.365 mgrm., while 0.6 C. Cm. could neutralise
this amount at least,—namely, that 1 C. Cm. was able to neutralise 0.61 mgrm.
SERIES No. IV.—Experiments to ascertain the amount of venom which 1C. Cm.
of a serum, which had been in Bombay for over three years, was capable of
neutralising.
This serum had been in the possession of the Secretary of the Bombay
Natural History Society for at least three years. Calmette informed us that
it was at least three years old, probably more.
Animal.
Amount of dried
venom
in Milligrammes.
Amount of ser
in C. Cm.
Result
.
Rat
1 . . .
0 . 4
0.25
Died in 1½; hours.
Rat 2
. . .
0 . 4
0.5
Died in 1 ½ hours.
Rat 3
. . .
0.4
0.75
Died in 3 hours.
Rat 4
. . .
0.4
0.75
Very ill for 48 hours ; recovered.
Rat 5
. . .
04
0.85
Died within 36 hours.
Rat 6
. . .
0.4
1.0
Died in 6½ hours.
Rat 7
. . .
0.4
1.0
Died in 9 hours.
Rat 8 .
.
.
0.4
1.0
Ill; recovered.
Rat 9
. . .
0.4
1.15
Died after 3 days.
Rat 10
. . .
0 . 4
1.25
No symptoms.
Rat 11
. . .
0 . 4
1.5
No symptoms
.
15
From the above series of experiments we can conclude that 1'15 C. Cm. of
this serum failed to completely neutralise 0'4 0'035 mgrm.=0'365 mgrm.,
while 1'25 C. Cm. did neutralise this amount at least. Therefore, 1 C. Cm. of
this serum was able to neutralise 0'29 mgrm.
SERIES No. V.—Experiments to ascertain the amount of venom which 1 C. Cm.
of a serum of the same age as that used in Series No. IV, but which had been
kept during most of the time in a comparatively cool place, was capable of
.
The serum used in this series of experiments was got from Captain Mitchell
of Nasik. It was imported to India at the same time as the serum used in the
experiments detailed in series No. IV.
After being stored in Bombay it was sent to Nasik. The exact date when
this happened cannot be ascertained, as no record was kept of the event.
It was received at the laboratory from Nasik in October 1900. The experiments
were completed between 16th October and 13th November.
A n i m a l .
Amount of dried
venom
in Milligrammes.
Amount of serum
in C. Cm.
R e s u l t .
Rat 1 . . .
0 ' 4
0'25
Died within 3½ hours.
Rat 2 . . .
0'4
0 ' 2 5 Died within 3 hours.
Rat 3 . . .
0'4
0'25
Died within 7 hours.
Rat 4 . . .
0.4
0.3
Died within 4 hours.
Rat 5 . . .
0'4
0.35
Died within 4½ hours.
Rat 6 . . .
0'4
0'4
Died within 4 hours.
Rat 7 . . .
0'4
0'45
Died within 5 hours.
Rat 8 . . .
0'4
0'5
Died within 14 hours.
Rat 9 . . .
0'4
0 ' 5 Died within 4½ hours.
Rat 10 . . .
0'4
0 ' 5 Very ill for 24 hours ; recovered.
Rat 11 . . .
0'4
0'55
Died within 40 hours.
Rat 12 . . .
0'4
0 ' 6 Died within 50 hours.
Rat 13 . . .
0'4
0'65
Died within 54 hours.
Rat 14 . . .
0'4
0'7
Died within 50 hours.
Rat 15 . . .
0'4
0'7
Ill ; recovered.
Rat 16 . . .
0'4
0'75
No symptoms.
Rat 17 . . .
0'4
0 ' 7 5 Died within 8 days.
Rat 18 . . .
0'4
0 ' 8 No symptoms.
Rat 19 . . .
0'4
1'0
No symptoms.
Rat 20 . . .
0'4
1'25
No symptoms.
Rat 21 . . .
0'4
1 ' 5
No symptoms.
16
From the above series of experiments we can conclude that 0.75 C. Cm. of
this serum did not completely neutralise 0.4 — 0.035 mgrm.=0.365 mgrm., but
that 0.8 C. Cm. was able to do this. It is evident, therefore, that 1 C. Cm. of
this sample could neutralise 0.46 mgrm.
SERIES No. VI.—Experiments to ascertain the amount of venom which 1 C.
Cm. of serum received from Lieutenant-Colonel Gimlette, Indore, was able to
n e u t r a l i s e .
This serum was dated 17th October, 1896. At the time of our experiments
it was, therefore, five years old. It was imported to India in September 1899.
It arrived in Indore the same month, and was kept there till November 1900,
when it was sent to Bombay.
The experiments were completed between 27th November and 3rd Decem
ber.
Animal.
Amount of dried
venom
in Milligrammes.
Amount of serum
in C. Cm.
Result.
Rat 1 . . .
0.4
0.5
Died in 2 hours.
Rat 2 . . .
0.4
0 . 6 Died in 2 hours.
Rat 3 . . .
0.4
0.7
Died in 1¼ hours.
Rat 4 . . .
0.4
0 . 8 Died in 1¼ hours.
Rat 5 . . .
0.4
0.9
Died in 2 hours.
Rat 6 . . .
0.4
1 . 0 Died in 2 hours.
Rat 7 . . .
0.4
1.1
Died in 20 hours.
Rat 8 . . .
0 . 4
1 . 2 Died in 20 hours.
Rat 9 . . .
0.4
1 . 3 Died in 2¾ hours.
Rat 10 . . .
0 . 4
1.4
Died in 7½ hours.
Rat 11 . . .
0.4
1 . 5 Died in 19 hours.
Rat 12 . . .
0.4
1 . 6 Died in 90 hours.
Rat 13 . . .
0.4
1.7
Died within 67 hours.
Rat 14 . . .
0.4
2 . 0 Ill for 2 days ; recovered.
From the above series of experiments we can conclude that 2 C. Cm. was
the minimum amount of serum which was able to neutralise 0.4 — 0.035 mgrm.=
0.365 mgrm. In other words, 1 C. Cm. was able to neutralise 0.18 mgrm.
17
SERIES No. VII.—Experiments to ascertain the amount of venom which 1 C.
Cm. of serum received from Mr. Hankin, Agra, was able to neutralise.
This sample of serum bore the date 17th September 1895.
Mr. Hankin informed us that he had kept no record of the exact date when
he received this sample of serum, but that he had little or no doubt that he re-
- c e i v e d i t i n t h e y e a r i n w h i c h i t w a s p r e p a r e d . W e m a y , t h e r e f o r e , t a k e i t t h a t
this serum had been in Agra for over four years.
A n i m a l .
Amount of dried
venom in
Milligrammes.
Amount of serum
in
C. Cm.
Result.
Rat
1 . . .
0.4
0.7
Died in 5 hours.
Rat
2 . . .
0 . 4
0 . 8
Died in 5 hours.
Rat
3 . . .
0.4
0 . 9
Died in 8 hours.
Rat 4
. . .
0.4
1 . 0
Died within 48 hours.
Rat 5
. . .
0 . 4
1 . 1
Died in 3 ¾ hours.
Rat 6
. . .
0 . 4
1.2
Died in 9 hours.
Rat 7
. . .
0.4
1 . 2 5 Died in 19 hours.
Rat
8 . . .
0.4
1 . 3 Died in 9 hours.
Rat 9 . . .
0 . 4
1 . 4 Died in 9 hours.
Rat 10 . . .
0 . 4
1 . 4 Died in 30 hours.
Rat 11 . . .
0 . 4
1.5
No symptoms.
Rat 12
. . .
0 . 4
1.5
Died within 18 hours.
Rat 13
. . .
0 . 4
1.5
Died in 38 hours.
Rat 14
. . .
0 . 4
1 . 6 Died within 22 ½ hours.
Rat 15
. . .
0 . 4
1.6
Died in 18 hours.
Rat 16
. . .
0 . 4
1.7
Died within 18 hours.
Rat
1 7
. . .
0 . 4
1 . 7 Died in 16 ¾ hours.
Rat 18
. . .
0 . 4
1 . 8 Died within 18 hours.
Rat 19
. . .
0 . 4
1.9
Died within 18 hours.
Rat 20
. . .
0 . 4
2.0
Died in 24 hours.
Rat 21
. . .
0 . 4
2.0
Died within 17 hours.
Rat 22
. . .
0 . 4
2.25
Died within 17 hours.
Rat 23
. . .
0 . 4
2.5
Died in 46 hours.
From the above series of experiments we can conclude that 2.5 C. Cm.
of this serum could not neutralise 0.4 — 0.035 mgrm.=0.365 mgrm. It is
evident, therefore, that 1 C. Cm. could not neutralise even 0.14 mgrm.