of the Mammary Organs of the Kangaroo. 459 
teat, its life has been destroyed in every instance which I have 
hitherto met with. It seems therefore fair to infer in such 
cases, that the organization and general condition of the mar- 
supial young is intermediate between the state in which we find 
other classes of mammalia whilst inclosed in the uterus and 
after they have been brought forth; for it must be manifest, 
that in such cases the re-union of the lips of the immature ani- 
mal to the separated teat is prevented by an absence of those 
powers of volition with which other newly born quadrupeds are 
invariably endowed. Numerous other arguments, which I need 
not now instance, might be brought forward in proof of the fact, 
that the first period of extra-uterine existence in marsupial ani- 
mals is intermediate between the two states which I have just 
mentioned. | aud ! 
Now, as somewhat more than a mere matter of curiosity, it 
may be interesting to future inquirers to know at what period 
the re-union of a separated marsupial young one from the teat 
can be effected ; since at that period it may be presumed that 
the immature animal is no longer receiving involuntarily the 
nourishment of the mother ; and since we have reason to believe 
that it is at this time that the intermediate state of existence to 
which I have alluded will have ceased. 
This can only be known by repeated experimental examina- 
tions, made by others whose opportunity must be much more 
extensive than my own ; and for their information therefore I 
have to state, that I have repeatedly separated from its adherent 
teat the young of the kangaroo whilst perfectly naked and ap- 
parently blind, and at a time when its size was not equal to that 
of a large Norway rat; and that I have in more than one in- 
stance prevented a re-union for nearly two hours, with a view 
of ascertaining how far a constant supply of milk under such 
circum- 
