384 ESSAYS ano OBSERVATIONS 
frata farrounding the zuc/eus, their colour 
differing in fhades from a dark rufty toa 
pale afhy colour. Their fubftance, ex- 
cept where there is tartarous crafty re- 
fembles a fine hat or chamois leather 
when cut. 
Hifi, 7. IN the collection of curiofities 
kept by the Surgeons of this place, there 
is a ball taken out of the'ftomach of a 
horfe, which is nearly fpherical, and nine- 
teen inches in circumference. Its furface 
has fomething of the mulberry form, be- 
ing compofed of a great number of he- 
mifpherical knobs, about a quarter of an 
inch diameter, contiguous to each other. 
Their outward fhell looks like a thin 
eruft of. fandy clay; but within this 
the fubftance has the fame matted 
appearance as the human concretions 
have. 
Hif. 8. Bauus are alfo frequently 
formed in the ftomachs of cows. Three 
of them which were given to me, are a | 
moft exact fpheres of a black colour, com- 
pofed of an external hard tartarous cruit, 
. which | 
