[ *9 1 
makes ufe of, in mufcular motion. We explain by 
this, how it happens that an afs, who has fo much 
lefs brains than a man, is, notwithftanding, fo much 
ftronger, becaufe it has much more blood. 
Here then is a fecond fpring that affords thefe mon- 
gers a confiderable fupply; but though fufficient for 
their motions, it is not equal to that of an ordinary 
fcetus, and the violent agitations of their body arife 
from their great fenfibility, which we have juft now 
accounted for. Now, the blood in the fcetus, and 
efpecially in thefe, belongs to the mother ; they are 
furnifhed by her, as well with air, as with the 
nervous juice, and the animal fluid, which are ef- 
fential to her. Wherefore, as foon a thefe children 
are feparated from the mother, and deprived of that 
vital fource, all motion mull ceafe in them, as if 
they were fuffocated, that is, as in any other fuffo- 
cated fcetus. 
Let us conclude this account by a word or two on 
the caufe of thefe monfters. 
The great quantity of waters voided by the mo- 
thers of thefe children, proves that the principle of 
their monftrccity is a difeafe, a fort of dropfy, and 
even a kind of hydrocephalus , which had run off a con-* 
fiderable time before the labor. 
The two hydatides I found at the origin of the 
brachial nerves,, and which had evidently been the 
caufe of the mutilation of the upper extremities, are 
examples that help us to comprehend that of the other 
organs. On luppoflng a like diforder on the origin, 
of other nerves, which have their rife from the brain, 
it will be obvious that the organs, to which thefe 
nerves run, that is, where they convey the nervous 
D 2. fluid,. 
