142 
NATURE 
[| ECEMBER 6, 1906 
been removed was sealed up with some radium salt in 
September last, and at the present time no signs of growth 
have made their appearance, but if to a portion of the 
gelatin a soluble sulphate is added, a growth at once 
appears. ' 
A series of photographs has been taken by means of 
the large photomicrographic apparatus of Zeiss, using 
magnifying powers of from 400 to 4000 diameters. 
It thus seems to be quite clear that the cellular growth 
cannot be produced by radium or barium unless a sulphate 
is present, and other metals, save Sr and Pb, fail to pro- 
duce any result, because they do not form insoluble 
sulphates. 
The cellular form of these precipitates is probably due 
to the circumstance that the gelatin is liquefied by the 
actions of the salt, and each particle of precipitate is 
formed about a core of gelatin, so that the layer of barium 
sulphate forms a kind of sac or cell which is surrounded 
by the solutions of the salt in the liquefied gelatin. This 
cell may be permeable to the liquefied gelatin containing 
a salt in solution, which, passing through the cell wall, 
causes an expansion to take place, the limit of growth 
being controlled by some surface-tension effect. 
The conclusions which are drawn from a study of the 
photographs and direct examination under the microscope 
with high powers are that :— 
(1) The cells form round a precipitate of an insoluble , 
sulphate, and the energy of the growth of the cell depends 
upon the amount of sulphate present. : 
(2) Radium has no specific action in forming cells, any 
effect produced being due to the barium associated with it, 
and the purer specimens of radium salts are less satis- 
factory as cell-formers than the impurer ones. Probably 
pure radium salt would have no action except that of 
causing an evolution of gas. 
(3) The cells do not divide or bud, or show anything 
resembling ‘‘ karyokinesis,’’ their growth very quickly 
reaches a maximum, and they do not decay or split up, 
save as a consequence of the drying of the gelatin. If 
the cover glass is sealed down with cement, the cells 
have been observed to suffer no alteration in the course 
of four months. 
(4) Radio-active substances, unless they contain barium, 
do not give rise to the formation of cells. 
November 1.—‘ The Anzesthetic and Lethal Quantity of | 
Chloroform in the 
master and J. A. Gardner. 
Waller, F.R.S. 
The amount of chloroform present in the arterial blood 
of animals at’ various stages of anzsthesia has been 
accurately determined by the authors for the first time in 
this country. All observers who have worked at the ques- 
tion of chloroform-anzesthesia, including those members 
of the Special Chloroform Committee of the British Medical 
Association who have specially investigated this point, 
are agreed that chloroform is tenaciously held by blood, 
and that the transport of the drug from alveolar air to the 
cells of the body and the nervous system is probably 
effected by the red corpuscles. 
The authors have given in some detail an account of 
the researches recently undertaken by French observers, 
J. Tissot and Mansion, and M. Nicloux, who have 
improved on the original methods employed by Gréhant 
and Pohl by using the reaction described by Dumas in 
1821. To ascertain the amount of chloroform in blood, 
this is distilled off from the liquid, boiled with alcoholic 
potash, and the potassium chlorate thus obtained is 
titrated with silver nitrate. 
In the experiments now described, the amount of chloro- 
form in arterial blood at the moment when both the con- 
junctival and tail reflexes have disappeared, when the 
respiratory movements cease, and when the reflexes re- 
appear, has been calculated from the difference in the 
chlorine-content of the blood before and after the adminis- 
tration of the anzsthesia. The method of estimation was 
the well-known one introduced by Carius for determining 
the amount of halogen in organic compounds. and by the 
adoption of Gooch’s method of filtration and J. P. Cooke’s 
suggestion of washing the silver chloride precipitate with 
water containing a little silver nitrate, a very high degree 
NO. 1936, VOL. 75 | 
Blood.”’ By Dr. George A. Buck- 
Communicated by Dr. A. D. 
of accuracy was obtained. For the validity of this method 
the natural chlorine-content of the blood must be shown 
to remain constant during the course of any single set ot 
experiments. Several tables show that this is the case 
during prolonged anzesthetisation with ether, the actual 
deviations from the mean being only 0-00123 and 0-00165. 
The majority of the observations have been made on 
cats, since the phenomena of anzsthesia in these animals 
closely resemble those observed in man. In order to 
afford a means of comparison with the results obtained by 
the French observers on dogs, a few experiments were 
carried out on these animals. 
Since it is difficult in any given case to ascertain the 
exact moment when an animal is actually anaesthetised, 
the authors have been obliged to take the disappearance 
of both conjunctival reflexes as a fixed point, and the 
occurrence of the first asphyxial convulsion of the re- 
spiratory muscles as indicative of the lethal stage, and 
in order to obtain comparable results they have found that 
the experiments must be made on healthy, well-nourished 
adults, and that the animals must not be in full digestion. 
From the results of all the experiments it has been 
found that the amount of chloroform in arterial blood at 
the moment when the conjunctival reflexes disappear varies 
between 14 and 27-6 milligrams in 100 grams of blood. 
As others have noticed, the rate of induction of anzesthesia 
varies slightly in different animals, though the actual 
body-weight is a negligible factor. The curves given in 
the paper, which have been constructed from the vary- 
ing chloroform-content of the blood during anzsthesia, 
show that the rate of induction is a feature peculiar to 
each individual animal. The average lethal dose of 
| chloroform in 100 grams of blood is 4o milligrams. 
After anzesthesia the chloroform is eliminated with 
extreme rapidity, and though the rate of elimination varies 
in different animals, the rate of disappearance of chloro- 
form is far more constant than the rate of assumption. 
A considerable number of experiments devised to ascer- 
tain how chloroform when inhaled is distributed in the 
red corpuscles and plasma, show that the drug is primarily 
| associated with the corpuscles, and only gets into the 
plasma when the anaesthesia is pushed to an extreme point 
or a high percentage of the vapour is rapidly administered. 
From the results given in Table xvii. it appears that no 
less than 98-5 of the total chloroform in the blood was 
held by the corpuscles at the moment when the respiration 
ceased. 
The view of Desgrez and Nicloux that carbon monoxide 
is formed in the blood during intense chloroform-narcosis 
has not been verified by the few observations which were 
made to determine this particular point. 
November 8.—‘ Experimental Investigation as to De- 
pendence of Gravity on Temperature.’’ By L. Southerns. 
Communicated by Prof. W. M. Hicks, F.R.S. 
The object of this investigation is to determine whether 
the action of gravity on a given mass varies to any 
measurable extent when the temperature of the mass is 
altered. Experiments having the same object, but differ- 
ently carried out, were described by Poynting and Phillips 
in the Proceedings of the Royal Society, September, 1905, 
about a year after the commencement of the present work. 
These led to a null result, which receives confirmation 
from the experiments here noticed. 
The apparatus in its original form was constructed 
several years ago by Dr. Hicks. After some modification 
it was set up in the new university buildings at Sheffield. 
A mass of paraffin oil was used in the experiments. This ~ 
was contained in an air-tight, jacketed calorimeter, and 
suspended from one end of the beam of a balance, the other 
end carrying a suitable counterpoise. A coil of fine 
platinum wire was immersed in the oil, and by passing 
through this an alternating current, the temperature of 
the oil could be raised to the required degree. In order 
that this might be accomplished while the balance was 
freely suspended on its knife-edges, the current was con- 
veyed to the coil by means of two wires rigidly fixed to 
the beam, their ends being pointed and made just to dip 
into mercury cups which were placed in line with the . 
central knife-edges, and were joined up to the ex- 
ternal circuit. The connections between the wires and 
