132 INTESTINAL CONCRETIONS IN MILLERS 5 HORSES. 
yet is this statement repeated over and over again by Blaine, 
until we arrive at the last edition of his work. And still 
stranger, Mr. Percivall has fallen into the same error. After 
stating that the formation of calculi in the bowels of a horse 
should not surprise us, “ when we know that, on occasions, 
not only is much dust swallowed with his food, but that the 
voracious feeder is disposed, whenever he has the opportunity, 
to lick up and swallow a great deal of dirt. * * * * Even in 
the stable, dusty hay is often given, and oats full of grit and 
fragments of stones ;” he adds, “ Millers’ horses are said to 
be especially subject to these formations, from the circum- 
stance of their food consisting principally of bran and mill- 
dust. The millstones must necessarily impart more or less 
of their substance to whatever they grind into dust or meal, 
and this gritty or calcareous matter it is which becomes 
afterwards the principal component of these concretions.” 
I do not mean to deny the truth of the statement that a 
voracious feeder will take into his stomach strange substances, 
but these do not aggregate so as to form the concretions met 
with in millers’ horses so frequently. The Continental 
chemists long since analysed these accumulations, and found 
them to consist essentially of the ammonio-magnesian phos- 
phate. Professor Morton, in his published £ Essay on Cal- 
culous Concretions in the Horse, Ox, Sheep, and Dog,’ 
informs us that having examined one taken from the stomach 
of a horse, he found it to consist of “ the phosphate of 
ammonia and magnesia, a small quantity of silica, and mucus;” 
and he afterwards satisfactorily traces these constituents to 
their source. “ In the cereal plants certain of the phosphates 
are met with, and that, too, in somewhat considerable quan- 
tities ; it is then to the food that we are to look for their origin, 
coupled with a morbid state of the digestive function;” 
probably, the succus gastricus not being sufficiently active, 
so as to dissolve these phosphates. In this view he is 
supported by Liebig, who states, in his work on £ Organic 
Chemistry,’ that “ phosphate of magnesia in combination with 
ammonia is an invariable constituent of the seeds of all the 
grasses. It is contained in the outer horny husk. The bran 
of flour contains the greatest quantity of it. It is this salt 
which forms large crystalline concretions, often amounting 
to several pounds in weight, found in the Ccecum of horses 
belonging to millers.” 
I have purposely dwelt on this one particular formation, 
because it is in horses of millers that I have of late years found 
them, and they are all of the same kind. I am quite aware 
that differently constituted calculous concretions are met 
