ly, as you let it goe into the Dog, that
is to live.

_Thirdly_, I suppose the Dog that is to bleed out into dishes will endure
it the better, if the Dogs that are to be administred to supply his bloud,
be of near an equal age, and fed alike the day before, that both their
blouds may be of a neer strength and temper.

There are many things I have observed upon bleeding Dogs to death, which I
have seen since your departure from _Oxford_, whereof I shall give you a
relation hereafter; in the mean time since you were pleased to mention it
to the _Royal Society_, with a promise to give them an account of this
experiment, I could not but take the first opportunity to clear you from
that obligation, &c.

_So far this Letter;_ the prescriptions whereof having been carefully
observ'd by those who were imployed to make the Experiment, have hitherto
been attended with good success; and that not only upon Animals of the same
_Species_ (as two Dogs first, and then two Sheep) but also upon some of
very differing _Species_ (as a Sheep and a Dog; the former _Emitting_, the
other _Receiving_)

_Note_ only, that instead of a Quill, a small crooked thin {357} Pipe of
Silver or Brass, so slender that the one end may enter into a Quill, and
having at the other end, that is to enter into the Vein and Arterie, a
small knob, for the better fastening them to it with a thread, will be much
fitter than a strait Pipe or Quill, for this Operation: for so they are
much more easie to be managed.

'Tis intended, that these tryals shall be prosecuted to the utmost variety
the subject will bear: As by exchanging the bloud of Old and Young, Sick
and Healthy, Hot and Cold, Fierce and Fearful, Lame and Wild Animals, &c.,
and, that not only the same, but also of differing kinds. For which end,
and to improve this noble Experiment, either for knowledge, or use, or
both, some Ingenious men have already proposed considerable tryals and
Inquiries; of which perhaps an account will be given hereafter. For the
present we shall only subjoyn some.

_Considerations about this kind of Experiments._

1. It may be consider'd in them, that the bloud of the _Emittent_ Animal,
may after a few minuts of time, by its circulation, mix and run out with
that of the _Recipient_. Wherefore to be assured in these Tryals, that all
the bloud of the _Recipient_ is run out, and none left in him but the
adventitious bloud of the _Emittent_, two or three or more Animals (which