170 Transactions of the Royal Society of South Africa, 
Though carbolic acid was discovered in 1834 (by E-unge), it did not 
come into general use till 1866, when Lord, then Mr., Lister introduced it 
into practice in the treatment of wounds as a general surgical antiseptic. 
Carbolic acid is one of the hydroxyl compounds of benzol, and, like 
several of this series, is a strong antiseptic and preservative. It is easily 
soluble in water (1-88 at 16°), and in oils and several other media. 
It acts as a general protoplasm poison, and even in dilute solutions kills 
protozoa quickly unless in extremely attenuated dilutions. 
Plant cells are acted on in the same way ; ciliated epithelial cells and 
spermatozoa are killed at once. 
It precipitates protein both in solution and in the cells, and does not, 
like so many substances used in microscopical technique, enter intocombina. 
tion with the albumen to form a fresh compound. It can consequently be 
washed out with comparative ease. 
As a result it penetrates more rapidly and completely into the tissues 
than metallic or other substances which form insoluble compounds with 
albumen. 
It fixes both the cytoplasm and the nucleus without alteration or 
distortion, while it leaves all cell structure well defined and clear. 
It is of more than ordinary interest to note here that Lister, then 
engaged in developing his epoch-making ;life's work, antiseptic surgery, 
demonstrated in some early experiments the avidity with which epidermis 
and hair absorbed carbolic acid from its watery solution. 
He packed human hair in a test-tube, then covered it with a 5 per cent, 
•carbolic acid solution ; in half an hour one-half of the carbolic acid had 
been extracted from the solution. 
In another experiment he packed a glass tube open at both ends with 
hair, and whilst it stood upright carbolic acid solution was poured in at the 
upper end. For some time the liquid which flowed from the lower end of 
the tube contained no carbolic acid at all. 
At the same time that carbolic acid is a good fixative it is a preservative, 
and as such it has been largely used. 
I was much interested to learn from Hofrat Professor Paltauf, the 
distinguished head of the Laboratory for Experimental Pathology, Vienna, 
that he had examined tissues from an exhumed body which had been 
soaked in carbolic and buried for some considerable time. The body had 
been covered with carbolic acid in the hopes of destroying all traces of a 
crime. He had been much surprised to find the remarkable state of 
preservation of the tissues, and microscopical sections, especially of the 
stomach, etc., gave particularly good results. 
The cause of this was not fully appreciated at the time, but was made 
clear on an examination of my preparations. 
Largely used in microscopical technique both in histological and 
