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experiments, experimental technique had not reached so high a stage of refinement 
as it has done at the present time. In the meantime we have become acquainted 
with, and have learned to take into account, the influence of temperature, time, dilution 
and other factors upon the strength and’ proportionality of the combination, and we 
now know that the law of multiple proportions does not apply universally, but only 
approximately. At the suggestion of Dunbar the authors have submitted to control- 
tests the conditions of combination between the toxin of rye-pollen and its anti-serum, 
and have been able to confirm the validity of the law which has been found to exist 
in the case of ambrosia-toxin and its antitoxin. They took as their starting-point the 
new toxin of high activity prepared by a special process‘), and tested it, together 
with Pollantin, on five patients in multiples of size of 1, 5, 10, 20, 40 and 80. It was 
found that, contrary to the assumption of Prausnitz, both these substances neutralised 
each other in conformity with the law above-mentioned, provided care was taken that 
the change of the conditions of admixture which manifests itself in the testing of the 
higher multiples is counteracted by the use of dry serum, and also that the mixtures 
are only tested after they have been left for three hours in a thermostat. The object 
of the last-named measure of precaution was the conversion of the initial loose 
physical combination into a stable chemical compound. Comparative experiments with 
mixtures of toxin and antitoxin which had been left standing partly for 15 minutes 
and partly for 3 hours at a temperature of 37°, and both of which, when tested in 
the eye of the patient, had been found to be neutral, showed (after the mixtures had 
been passed through a gelatinised Berkefeld-filter), this difference, that the 15 minute- 
mixture had partly recovered its toxicity, whereas the mixture which had been 
prepared three hours previously had remained neutral after ultra-filtration. In order 
to compensate for the weakening action of filtration upon the toxin, the toxin-solution 
had been passed through the filter prior to its admixture with the serum, so that 
repeated filtration had no further reducing effect upon the toxicity. 
The authors draw the following conclusions from their experiments: — 
The neutralisation of the hay-fever poison by the corresponding antitoxin rigidly 
follows the law of multiple proportions. A reversible physical combination is followed 
in the second phase by a firm chemical combination. The toxin of hay-fever is more 
stable towards heat than its corresponding antitoxin. Hence, the first-named may 
again be liberated from neutral mixtures by heating to 72°. 
CHEMICAL PREPARATIONS AND DRUGS. 117 
We may here call the attention of our clients, and in particular of the pharmacists | 
among them, to the fact that we are prepared to exchange old tins of liquid Pollantin 
bearing control-numbers from 166 (inclusive) downwards for fresh serum, and we 
therefore request them to look out such numbers from their stock and return them 
to us. Upon receipt the new tins will be forwarded immediately. Powdered Pollantin, 
if properly stored, has unlimited keeping quality, and for that reason, as we have 
repeatedly stated, we cannot undertake to exchange it. 
Rose Oil, artificial. This exquisite substitute for genuine rose oil has been 
particularly appreciated last year, because the high prices of Bulgarian oil made the 
employment of the last-named article impossible for many of its regular consumers. 
Fience, compelled by necessity, many of those who were prejudiced against the syn- 
*) Comp. Report April 1913, 118. 
