510 
PHAEMACEUTICAL MEETING. 
that much loss of product occurs, from the difficulty of condensing the vapours, 
and from the more complex nature of the reaction. 
It has long been observed, in making spirit of nitric ether by the London 
process, that the nature of the product depends, to some extent, upon the quan¬ 
tity of ingredients operated upon, and the manner in which the heat is applied. 
If a small quantity of the mixture be submitted to distillation in a retort at as 
low a temperature as is sufficient for effecting slow distillation, the quantity of 
distilled product indicated in the Pharmacopoeia may be drawn over without 
any appreciable amount of nitrous ether being formed, so that the product in 
such case would be little else than pure spirit. In operating on larger quan¬ 
tities, however, and especially in conducting the process with a steam-jacketed 
still, a better result is obtained, the distilled product being richer in ether, in 
consequence of the higher temperature attained in the process. But even in 
this case the result is unsatisfactory, for not only is the amount of ether pro¬ 
duced small in relation to the nitric acid employed, but most of the acid and 
much of the spirit, mixed in the proper proportions for producing ether, would 
be left in the still as a waste residue, if the process be stopped at the point in¬ 
dicated. Practically manufacturers do not stop at this point, but continue 
the distillation, and thus greatly increase the strength of the product. There 
is, nevertheless, a limit beyond which the distillation cannot be carried without 
great detriment to the product, as the reaction becomes more and more complex 
as the process proceeds, and finally nitrous fumes are abundantly formed. 
The nature of the reaction which occurs in this process has been investigated 
by many able chemists, who have shown that it varies greatly according to the 
conditions present, and that it is very complex, especially when the action is 
intense. Dr. Golding Bird, many years ago, and more recently Dr. Debus, 
have contributed to this investigation. Among the products of the reaction, in 
addition to nitrous ether and aldehyd, chemists have enumerated carbonic, for¬ 
mic, acetic, oxalic, lactic, saccharic and glyoxalic acids. Hydrocyanic acid is 
also said to have been produced in some instances. I do not propose to enter, 
on the present occasion, into this part of the subject, beyond alluding to the 
fact, that, as these bodies are produced, there must be loss of alcohol and nitric 
acid, and there may be a material alteration effected in the composition of the 
distilled product. Intense action is therefore to be avoided, both on the ground 
of economy, and also with a view to the quality of the product. 
I believe that the sweet spirit of nitre of commerce is always obtained by the 
distillation of a mixture of nitric acid and spirit, but manufacturers no doubt 
vary their methods of operating according to their knowledge and experience. 
The objects they have especially in view are, the means of satisfying the re¬ 
quirements of their customers, and of competing with each other in regard to 
quality and price. The article is manufactured upon so large a scale, and its 
market value is defined within such narrow limits, that any proposed alteration 
in the long established process for its production, that would materially alter 
its character or enhance its price, would be very unhkely to be generally 
adopted. 
It is not in the dispensing of medical prescriptions that the great bulk of the 
sweet spirit of nitre of commerce is used, but as a popular remedy which the 
public are accustomed to prescribe on their own responsibility. As originally 
prepared, and as met with in commerce, it is an impure solution of nitrous 
ether in strong spirit. All the samples that I have ever examined, contain¬ 
ing any appreciable quantity of nitrous ether, have also contained aldehyd, 
and I therefore consider commercial sweet spirit of nitre to be essentially a so¬ 
lution of nitrous ether and aldehyd. All the attempts that have hitherto been 
made to exclude aldehyd have practically proved failures, either by excluding at 
the same time the nitrous ether, or by unduly increasing the cost of the process. 
