202 Mr. Cruikshank’s Experiments 
the smallest degree; the foetus was not visible; but I had often 
made the chick, in my experiments on the incubated egg, be- 
come visible, by dropping on the spot, where I knew it must 
be, a drop of distilled vinegar; by dropping the vinegar on the 
bottom of the little cups I had made, by cutting off the tops of 
the cells, the foetus instantly became visible. 
EXPERIMENT VI. 
Opened another, ninth day: foetus contained within its am- 
nion, floats in another fluid, between chorion and amnion, which 
are now at a considerable distance; this fluid jellies in proof spi- 
rit. Some corpora lutea have cavities, others none, nor the least 
appearance of orifice. The corpora lutea keep increasing as the 
foetus increases, are of a sand-red colour, and very vascular. 
EXPERIMENT VII. 
Opened a doe the eleventh day after coitus : ova very little 
larger than the last, nor the foetus : there were but two ova, 
though several corpora lutea. Some pellucid hydatids appeared 
hanging on the outside of the fallopian tubes. Could these be 
ova which had missed the passage ? they were vascular : the 
heart of the foetus was full of blood; the umbilical vessels very 
distinct, but no chord as yet, contrary to De Graaf. 
EXPERIMENT VIII. 
Opened a doe the fourteenth day: seven corpora lutea in one 
ovarium, and one in the other; only two ova in the horns of 
the uterus, one in each; that in the horn next one of the ovaria 
with one corpus luteum was blighted, and the foetus invisible, 
even with distilled vinegar ; in the other it was increased pro- 
