400 
PHARMACEUTICAL MEETING. 
in ether and fatty bodies, aud possesses no rotatory power when viewed with the 
polarizer. It combines easily with alkalies such as potash and soda, and forms 
soluble salts. Thymic acid possesses the important property of combining with 
skins and animal tissues, and rendering them completely imputrescible. When 
concentrated, it has an acrid and caustic taste ; but in a very weak solution one 
can only discover a flavour of thyme, and a sensation of cold similar to that 
produced by essence of peppermint. Thymic acid is extracted from oil of thyme, 
in which it exists in combination with a carbide of hydrogen called thymene, 
isomeric with oil of turpentine, C 20 H 16 . In treating oil of thyme with an 
aqueous solution of potash or soda, the thymic acid is dissolved, and forms a 
soluble thymate, the thymine is thus separated, as it does not combine with 
alkalies. In decomposing the thymate by an acid, the thymic acid is liberated ; 
it is then purified by washing, drying, and finally by distillation. Thymic acid 
can be obtained by submitting oil of thyme to extreme cold, in which case it 
crystallizes. That which is extracted by potash, even if submitted to ever so 
low a temperature, does not solidify, even if crystals of the modification obtained 
by freezing be thrown into it, so as to induce a formation of crystals. There¬ 
fore, thymic acid exists in two isomeric states. The product obtained from oil 
of caraway presents an analogous phenomenon. By the use of sulphydrate of 
ammonia, carvol is obtained, whilst the potash process furnishes an isomeric 
compound, carvacrol, which is distinguished from carvol by certain reactions. 
This similarity of properties between thymic and phenic acids, as well as the 
agreeable smell of the former, induced me to employ it in medicine, and satis¬ 
factory results made me persevere in my researches. 
Dr. Paquet willingly experimented on this new product, and last December 
a communication, presented to the Anatomical Society of Paris, confirmed the 
idea of its antiseptic properties. Since then, many have studied its properties, 
and it is to be hoped that ere long thymic acid will altogether replace phenic 
acid and creasote in,medicine. 
Dr. Attfield did not know in what relation the author of the paper might 
stand to the Pharmaceutical Society, but it must be very pleasant to know 
that a Continental pharmacist sent them a paper. It showed that an interest 
was excited on the Continent in favour of British pharmacy and the labours of 
the Pharmaceutical Society. There were some points adverted to by the 
author, of which he (Dr. Attfield) should like to notice three. The first was 
as to the commerce of carbolic acid. He did not think that the author could 
know the extent to which carbolic acid was used in this country, or he would 
have hesitated before saying that the article had not generally been accepted. 
Secondly, the author, in his opinion, seemed to lay too great stress on the value 
of chemical homology as indicative of the properties of bodies. He very properly 
noticed that thymic acid was a homologue of phenic acid, otherwise called 
carbolic acid ; but it was separated to a pretty wide extent—as wide as that 
which separated acetic acid from valerianic acid; and no one would think of 
substituting one of these for the other. Then there was another matter of im¬ 
portance in a commercial point of view, which had not been touched upon by 
the author. He suggested this homologue of carbolic acid as a substitute fcr 
carbolic acid. They could obtain carbolic acid in large quantities, but where 
were they to obtain large quantities of thymic acid ? So far as he knew, the 
garden thyme —Thymus vulgaris —gave something like sixty drops of oil per 
pound of substance, and the common thyme —Thymus Serpyllum —gave about 
the same quantity. Then there was thymic acid in horse-mint, he did not 
know to what extent, but he presumed it would not give them much more 
than the garden or common thyme. And, lastly, they had the same substance 
occurring in the essential oil of Ptychotis Ajowan , of which Dr. Stenhouse 
