BULLETIN OF THE BUSSEY INSTITUTION. 271 
had any unpleasant taste, and since the oxide was in the condition 
of a very fine smooth powder. Inasmuch as the first mixture 
of ochre and oil was sticky and the surface of the balls was un- 
pleasantly oily, or moist, as it were, it was thought that this cir- 
cumstance might possibly have repelled the animals, but on pre- 
paring balls of ordinary putty that were similarly sticky and oily, 
they were readily eaten by the mice. 
In order to determine whether it might not perhaps be true that 
the mice refused the ochre because of its being really hurtful to 
them, they were fed with putty made of mixtures of red ochre and 
whiting, which they ate tolerably readily though less freely than 
pure whiting-putty. For example, three mice ate 4 balls per day 
of putty prepared from a mixture of 4 red ochre and # whiting. 
Next day they ate 4 balls made from a mixture of $ red ochre and 
4 whiting, their dung being all the while of a bright red color, but 
they subsequently refused putty made from a mixture of 3? red 
ochre and 4+ whiting, that is to say, they ate hardly any of it. 
As will be seen further on, under carbonate of baryta, it is pos- 
sible that the whiting protected the ochre from being acted upon 
by the gastric juice of the animals. That is to say, it is not alto- 
gether unlikely that the animals were made uncomfortable by such 
action in the case of the plain ochre, or that the ochre was un- 
acted upon when mixed with a great excess of the more soluble 
whiting. 
Yellow Ochre was hardly any more acceptable to the mice than 
red ochre. At first, when offered to them merely admixed with 
oil, they refused to eat it; but when mixed with whiting and oil 
they ate it rather readily. ‘Thus, three mice ate 6 balls made from 
a mixture of + yellow ochre and # whiting, in the course of one 
day ; 5 balls made from a mixture of $ yellow ochre and 4 whiting 
in the course of the next day, and 4 balls of the same the day 
after. On the day following they ate 5 balls made from a mixture 
of 3 parts yellow ochre and one part whiting, out of 6 balls that 
were offered them. Finally they were given a number of balls 
made from yellow ochre alone (plus oil, of course) without any 
whiting, and they ate two of the balls during the first day and 
nearly three on the second day. The dung was of a clear yellow 
color during the continuance of these trials, but not of the enor- 
mous size which was so noticeable when whiting alone was used. 
It was remarkable how soon this yellow dung began to appear 
