ECONOMY OF THE BODY———II
145
extract.
The effects of the thyroid are indeèd very similar
to those produced by'inci‘ease of temperature. What
they play in the development and life;df shes is still
unknown.
The same may be saidof the supra—renal
which are well—developed in shes, and the head kidney.
‘
The latter is one of the, most complicatedorgans in
shes.
Even in the earliest stages, when perhapsstillfunc—
tioning as akidney, it seems to take some part
for:
mation of the red blood corpuscles.
What its function is
later, is_ problematic; it, is always richly supplied
blood.
Other mysterious glands are found in the skull
in connection Withthe brain, pitùitary body below, pineal ,
and parietal bodies above (Fig. 44), endolymphatic sinus
of Dipnoi.
‘p‘ineal body and parietal gland form a kind
of eye
Lamprey (Petromyzon), but in other shes the
“
eye
” does not develop and they seem to have been diverted,
_
-
like thethyroid and thymus, to more general purposes.
,Lastly, mention should be made
the hormones
‘
sexual organs.
Likethe pancreas these organs have at leaSt
two functions,and the hormones carried aWay from them by
'
,
‘the'blood—and—lymph to other parts of the body
__
general-activities ofthe organism,
'
parts such as the
seëôndàrÿëèXuàl Characters;
=
1
az
,
?.i.
5
_
It has always been “a mystery that
characters, such as different coloration, nsilarger—‘in one '
sex than in the other, should be present long before the
respective shes became mature. But there seems no
_
mystery about the possibility of these hormones acting as
.
soon as the sexual organs are present, and becoming
inuential as the latter ripen. Hence we can understand
why the pectorals of the male Cottus, for example, become
serrated before the
are
deposited, why the male
.
-Gastrosteus begins to construct a nest before he has _‘chosèn
,
'
a partner, and why the male Carplings, remarkable
_
“ _ ,
brilliant coloration at all times, are always s0 urgent
in their
behaviour“ towards
11
_
—
,
‘
Our' conception] of“Whatis meant ;byÇïheredity __is "also
'
145
extract.
The effects of the thyroid are indeèd very similar
to those produced by'inci‘ease of temperature. What
they play in the development and life;df shes is still
unknown.
The same may be saidof the supra—renal
which are well—developed in shes, and the head kidney.
‘
The latter is one of the, most complicatedorgans in
shes.
Even in the earliest stages, when perhapsstillfunc—
tioning as akidney, it seems to take some part
for:
mation of the red blood corpuscles.
What its function is
later, is_ problematic; it, is always richly supplied
blood.
Other mysterious glands are found in the skull
in connection Withthe brain, pitùitary body below, pineal ,
and parietal bodies above (Fig. 44), endolymphatic sinus
of Dipnoi.
‘p‘ineal body and parietal gland form a kind
of eye
Lamprey (Petromyzon), but in other shes the
“
eye
” does not develop and they seem to have been diverted,
_
-
like thethyroid and thymus, to more general purposes.
,Lastly, mention should be made
the hormones
‘
sexual organs.
Likethe pancreas these organs have at leaSt
two functions,and the hormones carried aWay from them by
'
,
‘the'blood—and—lymph to other parts of the body
__
general-activities ofthe organism,
'
parts such as the
seëôndàrÿëèXuàl Characters;
=
1
az
,
?.i.
5
_
It has always been “a mystery that
characters, such as different coloration, nsilarger—‘in one '
sex than in the other, should be present long before the
respective shes became mature. But there seems no
_
mystery about the possibility of these hormones acting as
.
soon as the sexual organs are present, and becoming
inuential as the latter ripen. Hence we can understand
why the pectorals of the male Cottus, for example, become
serrated before the
are
deposited, why the male
.
-Gastrosteus begins to construct a nest before he has _‘chosèn
,
'
a partner, and why the male Carplings, remarkable
_
“ _ ,
brilliant coloration at all times, are always s0 urgent
in their
behaviour“ towards
11
_
—
,
‘
Our' conception] of“Whatis meant ;byÇïheredity __is "also
'