INTRODUCTION OF MEDICINAL SUBSTANCES IN MILK. 167 
most difficulty by the ruminant. Next to it in difficulty 
came mercurials, ferruginous and arsenical preparations being 
much more easily tolerated, while alkalis, and the chloride of 
sodium were always taken with pleasure by the animal, the 
latter being employed as an adjuvant with respect to other 
substances. The milk of animals thus treated became richer 
in casein and butter, this being probably due to the regimen 
employed. 
M. Boudet, while admiring the persevering efforts of M. 
Labourdette, carried on through ten years, still could not 
admit that the results promised to prove of much practical 
utility. The small quantity of iodine, for example, that 
could be thus communicated to the milk, rendered this fluid 
far inferior in this respect to cod-liver oil; and while in the 
latter it existed in a natural organic combination, in the 
former it was only got in by doing violence to the habits of 
the animal. To act therapeutically, very large quantities of 
this milk-diet would be required, which might be ill-supported 
or in other respects objectionable. 
M. Trousseau observed that he did not believe that the 
quantity of a substance administered constituted all its con¬ 
sequence. Thus, for example, in the treatment of chloro- 
anaemia by iron, it was long believed that the iron was only 
of efficacy when it gained a bodily entrance into the blood, 
to supply the deficient colouring matter. It was believed 
that the minute portions of iron wanting to the blood of a 
chlorotic woman, were replaced by a certain amount of the 
enormous quantities taken by the mouth. This theory of 
the action of iron is now pretty generally abandoned. It is 
admitted that it acts to a certain extent by modifying the 
functions especially operating on the assimilatory functions 
in such a manner that small portions of iron may be absorbed 
and utilised, independently of the quantity that has been 
administered, i. e., that the assimilation operates just as well 
upon the iron introduced by aliments, as upon that which 
may be given in large doses. What is here said of iron may 
be repeated concerning other medicinal substances to which 
a purely dynamic action is very generally attributed. Mer¬ 
cury, for example, acts in no other manner in syphilis. No 
one ever supposed that the direct contact of the mercury 
with each living particle is necessary for the purpose of 
neutralising the syphilitic virus throughout the economy. 
If this were the case, it is evident that the milk of a cow 
submitted to the mercurial regimen, in order to be efficacious, 
should contain far larger quantities of mercury than have 
been discovered in it. “ But I am convinced that this milk, 
