XGG 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[August 20, 1971. 
he prevented; while if the dose of atropia be 5-3 grains 
or more, the region of successful antagonism is left, and 
death occurs. With one and a half times the minimum 
fatal dose of physostigma, successful antagonism was 
produced with doses of atropia ranging from *02 grain to 
4 - 2 grains: with twice the minimum fatal of physo¬ 
stigma, with doses of atropia ranging from ‘025 grain to 
3*2 grains; with two and a half times the minimum fatal 
of physostigma, with doses of atropia ranging from *035 
grain to 2*2 grains; with thrice the minimum fatal of 
physostigma, with doses of atropia ranging from '06 grain 
to 1*2 grain; and with three and a half times the mini¬ 
mum fatal dose of physostigma, with doses of atropia ran¬ 
ging from *1 grain to ’2 grain. Successful antagonism 
could not be obtained above this dose, and, accordingly, 
three and a half times the minimum fatal dose of physo¬ 
stigma would appear to be about the largest quantity 
whose lethal action may bo prevented by administering 
atropia five minutes previously. 
A similar series of experiments has been made, in 
•which physostigma was administered five minutes before 
atropia, and the results were essentially the same, except¬ 
ing that the region of successful antagonism was found 
to be more limited. 
Series of experiments were also made, in each of which 
the doses of physostigma were the same, and the doses 
of atropia varied; while with each dose of atropia, 
several experiments were made which differed from each 
other by a difference in the interval of time between the 
administration of the two substances. 
It seemed of interest to ascertain what dose of atropia 
is required to produce death with a dose of physostigma 
below the minimum fatal. The experiments performed 
for this purpose show that when one half of the mini¬ 
mum fatal dose of physostigma is given five minutes 
after atropia, so large a dose of the latter substance as 
9-8 grains is required in order to cause death; recovery 
taking place with doses ranging from 3 to 9 A grains. 
The minimum fatal dose of sulphate of atropia given 
alone was found to be twenty-one grains for a rabbit 
weighing three pounds. It is, therefore, remarkable 
that the -^^ths of a grain can prevent a dose of physo¬ 
stigma, equal to the minimum fatal, from causing death, 
and that the T \jth of a grain is capable of rendering non- 
fatal a dose of physostigma, equal to three and a half 
times the minimum fatal. 
Excepting dilatation of the pupils, these minute doses 
of atropia, and indeed any dose capable of antagonizing 
the lethal action of physostigma, are unable to produce 
any symptom recognizable by a mere inspection of the 
animal. Still, they undoubtedly produced energetic 
physiological effects—effects, however, which it is un¬ 
necessary to describe in this brief abstract. It is suffi¬ 
cient to point out that the notion, which exists in many 
quarters, that rabbits can scarcely be affected by atropia 
is an erroneous one. 
Without referring to the other results obtained in his 
investigation, the author pointed out, in conclusion, that 
unless the antagonism between any two active substances 
be examined in the manner indicated in this communica¬ 
tion, no satisfactory proof of its existence can be obtained. 
The superficial area of the region should always be 
defined, otherwise indications of antagonism obtained by 
one observer will be liable to be discredited by those 
who subsequently examine the subject. The first ob¬ 
server may succeed in performing an experiment within 
the area.of successful antagonism, and thus feel satisfied 
of its existence; but his successors may fail in obtaining 
any proof by so varying the dose of one or other sub¬ 
stance as to pass the limits of the region of success. 
Peeling assured that many examples of successful an¬ 
tagonism, besides the one he had the honour of bring¬ 
ing before the Society, will yet be discovered, the 
author could not avoid the conclusion that the imperfect 
methods of investigation hitherto pursued are account¬ 
able for the absence of success that has attended the 
numerous researches made on this subject—a subject, it 
need scarcely be added, of tho greatest importance to 
toxicology and to scientific therapeutics. 
THE GASEOUS AND LIQUID STATES OF MATTER. 
BY THOMAS ANDREWS, M.D., F.H.S., 
Vice-Tresident of Queen's College , Belfast. 
{Concluded from page 145.) 
At 32°-5 the fall, when liquefaction might be expected, 
is less abrupt than at 31°T ; and at 35 0, 5, although still 
manifest, it is further reduced. At 48°T the fall shown 
at lower temperatures can no longer be distinctly ob¬ 
served, and the curve representing the change of volume 
approximates to that of a perfect gas. There can be 
little, if any, doubt that at a higher tomperature carbonic 
acid would behave under augmenting pressures nearly 
as nitrogen or hydrogen.* 
I have frequently exposed carbonic acid, without mak¬ 
ing precise measurements, to much higher pressure than 
any of the foregoing, and have made it pass without 
break or interruption from what is regarded by every 
one as tho gaseous state, to what is, in like manner, 
universally regarded as the liquid state. Take, for 
example, a given volume of carbonic acid gas at 50° C., 
or at a higher temperature, and expose it to increasing 
pressure till 150 atmospheres have been reached. In 
* These different modes of passing from the gaseous to 
the liquid state are admirably illustrated by a solid model 
constructed by Prof. J. Thomson, which was exhibited at the 
lecture. I have been favoured by Prof. Thomson with the 
following description of this model:— 
“ The model combines Dr. Andrews’ experimental results 
in a manner tending to show clearly their mutual correla¬ 
tion. It consists of a curved surface referred to three axes 
of rectangular co-ordinates, and formed so that the three 
co-ordinates of each point in the curved surface represent, 
for any given mass of carbonic acid, a pressure, a temperature 
and a volume, which can coexist in that mass. 
“ In Dr. Andrews’ diagram of curves, published in his 
naper in the ‘Transactions of the Royal Society for 1869,’ p. 
583, the experimental results, for each of several tempera¬ 
tures experimented on, are combined in the form of a plane 
curved line referred to two axes of rectangular co-ordinates. 
The curved surface in the model is obtained by placing these 
curved lines with their planes parallel to one another, and 
separated by intervals proportional to the differences of the 
temperatures to which the curves severally belong, and with 
the origins of co-ordinates of the curves situated in a straight 
line perpendicular to then.* planes, and with the axes of co¬ 
ordinates of all of them parallel in pairs to one another, and by 
cutting the curved surface out so as to pass through those 
curved lines smoothly or evenly. 
“ The curved surface so obtained exhibits in a very obvious 
way the remarkable phenomena of the voluminal conditions 
at and near the critical point of temperature and pressure in 
comparison with the voluminal conditions throughout other 
parts of the indefinite range of gradually-varying tempera¬ 
tures and pressures. This curved surface also helps to afford 
a clear view of the nature and meaning of the continuity of 
the liquid and gaseous states of matter. It -does so by its 
own obvious continuity throughout the expanse to which it 
might be extended round the outside of the critical point in 
receding from the range of the points of pressure and tem¬ 
perature where an abrupt change of volume can occur by 
gasification or condensation. On the curved surface in the 
model, Dr. Andrews’ curves for the temperatures 13°T, 21°*5, 
31°T, 3o°*5 and 48°T Centigrade, from which it was con¬ 
structed, are shown drawn in their proper places. The model 
admits of easily exhibiting in due relation to one another a 
second set of curves in which each curve would be for a 
constant pressure, and in which the co-ordinates would re¬ 
present temperatures and corresponding volumes. It serves 
generally as an aid towards bringing the whole subject clearly 
before the mind.” 
