52 
COD-LIVER OIL AS A CURATIVE AGENT. 
related in their chemical and physical properties, and as the 
compounds of bromine had been least examined, they were 
especially chosen ; and I think I proved that the physiolo- 
gical activity of these bodies was as their solubility and their 
facility of decomposition, with this allowance, that as chlorine 
is the more active element of the three, chemically, so it and 
its compounds are the more active of the three physiologically, 
cateris paribus. We find everywhere bromine and its com- 
pounds occupying an intermediate place between the others 
physiologically as they do chemically. 
“ In the electro positive salts — say, the chloride, bromide, 
and iodide of potassium — the chloride is the least easy of 
decomposition and the least soluble, the bromide more so, 
the iodide most, in the ratio of their activity. When w T e come 
to the electro-negative compounds — say, those of mercury — 
when the affinities come to be inverted, there the physiolo- 
gical and medicinal pow ers are inverted also ; for instance, 
iodine will decompose the chloride of mercury, while it will 
not decompose the chloride of potassium, and the chloride 
here is the most active, the bromide less so, the iodide least. 
Now I account for this by supposing that the activity of such 
substances depends in great part upon a series of molecular 
changes which they produce in the system, and that the 
elements liberated in the nascent form in the system produce 
a series of combinations and decompositions ; but the fact 
remains, that these bodies are closely related, and as cod- 
liver oil contains more chlorides than bromides or iodides, 
the activity of it may just as w ell be attributed to the first 
class as to the others. But omne ignotum est pro magnijico. 
In the ‘Archives Generates d’Anatomie/ for 1846, there is a 
paper which w T ould seem to controvert some of these views ; 
but for the present I shall content myself with stating that I 
adhere to them. 
“ The late Mr. West, of Leeds, in an analysis of the mineral 
w ater at Shotley Bridge, in the county of Durham — which, 
if his statement be correct, has w rongly fallen into desuetude 
— states that there are traces of bromine, and attributes great 
probable pow r ers to it. Now, as the proportion of bromides — 
for of course the bromine must exist in combination — is in in- 
finitesimal proportion to the chlorides, this idea is another 
illustration of the hallucination w r hich many men appear to 
entertain with regard to these bodies. 
“ As a further illustration of the relationship between all 
the properties of the chlorides, bromides, and iodides, I may 
give an extract from the recent letter of Dr. Cogswell on the 
‘Employment of the Chlorate of Potass in Cholera,’ pub- 
