214 SECTIONAL ADDRESSES. 
some degree of certainty, that beneficial results will follow such adjust- 
ments, but in most cases the attempt must be regarded as an experiment, 
the results of which may or may not justify the continued use of the salt 
mixture tried. 
It is obvious that the use of a stereotyped salt mixture with different 
rations, and for animals of different ages, and even of different species, 
is not warranted. In feeding experiments errors arise from the assumption 
that the addition of such mixtures obviates any necessity for further 
consideration of the mineral requirements of the animal, or of the influence 
which may be exercised by inorganic salts present in foodstuffs, the value 
of which is being tested. Under practical conditions, the use of such fixed 
mineral mixtures proves beneficial in many cases because they are rich 
in those inorganic constituents which are most frequently deficient in 
concentrates, but in cases where the ration is already rich in some of the 
minerals present in the mixture, the resulting excess may be harmful. 
No mineral mixture is a panacea. 
Our knowledge of this subject is, therefore, still so scanty that it forms 
a very uncertain guide to the stock-farmer. It is sufficient, however, to 
warrant his testing, under practical conditions, some of the results which 
have been obtained under experimental conditions. The results of such 
tests, if positive, would secure the early application in practice of informa- 
tion which we already possess, and, whether positive or negative, would bea 
valuable guide to further efforts to increase that part, of our knowledge 
which is of immediate practical value. 5 
In conclusion it may be of use to recapitulate briefly the points of 
practical interest brought out in this rather discursive address and then 
to indicate the direction in which research in this subject is proceeding. 
An attempt has been made to establish the following three propositions : 
(1) The mineral elements play such an important part in the physio- 
logical processes of the animal body that serious pathological conditions 
develop when the supply in the food does not meet the requirements of 
the animals. 
(2) Under modern intensive methods in animal husbandry these 
pathological conditions due to deficiency or lack of balance of the mineral 
matter of the food are liable to occur to such an extent that they may be 
the cause of considerable loss in the industry. A 
(3) This loss can, to some extent, be reduced by the application of 
the knowledge we already possess. 
In the cursory survey of mineral metabolism undertaken here, one is _ 
struck by the fact that the view of this subject which has been attained _ 
by research has served to reveal the existence of unexplored regions of — 
biology rather than to define the ground immediately in front of us. The 
academic research worker scaling new heights can see his way almost as 
well as those of us who are slowly following after, trying to exploit the ; 
territory already won. We, who are interested chiefly in obtaining a sure 
ground for the progress of the science of animal husbandry, can by prac- 
tical experimentation, help to map out the road to that position where 
we will have the knowledge necessary to adjust rations, so that the mineral 
requirements of animals will be adequately met, and some of the loss 
caused by malnutrition eliminated. The time has come when a larger 
