given by Huus (Zoc. cit.) Carlisle carried out experiments along the
following lines using Cionn inta~tinnlis and Phallwia ntammillata as
experimental animals.
(a) Mamrntilian chorionic gonadotrophin was injected into test
animals and distillod water into oolitrols. Itegardless of the site of
injection the gonadotrophin stirnulatod diecharge of gametes about 20
hours later (see also Carlisle, 1964, with reference to these experiments).
If the heart had previously been destroyed and the blood drained, this
response (shedding of gametes) only occurred if injection waa directly
into the neural region but not if injected into the gonad or elsewhere in
the body. These experiments could be interpreted to mean that the
hormone induces gamete release but does not affoct the gonads directly
and probably only through the intermediary of the nerve ganglion.
(b) The nerves between the ganglion and the gonads were sectioned
and gonadotrophin was then injected into the body as above. Under
these circumstances there was no positive response of gamete release
but if the gonadial nerve and ganglion were left intact and all other
nerves from the ganglion were severed, then there was a response of
gamete release. Furthermore if the ganglion was left intact but the
neural gland wa8 destroyed there was still a positive response of gamete
release when gonadotrophin was injected into the ascidian. These
experiments can be interpreted to mean that mammalian chorionic
gonadotrophin stimulates the nerve ganglion which in turn stimulates
release of gametes.
(c) When instead of using chorionic gonadotrophin a highly concentrated extract of ascidian neural gland was injected (about 100
glands per injection dose) a similar positive response of gamete dkcharge was elicited.
(d) Gametes were also released when an ascidian was fed with a
suspension of gametes of its own specie8 but not if fed with gamete?
from another species of ascidian.
From these experiments Carlisle concluded that the neural gland
functions in the release of gametes in the manner suggested by HUUR
(loc. cit.) but through the following chain of events:
Gametes in the inhalant water current are taken into the gland.
Gametes stimulate the gland to secrete B hormone.
The hormone excites the ganglion.
Nervous pathways from the ganglion through the gonadial nerve
stirnulate the release of gametes.
While the experiniental techniques used by Carlisle appear to have
been sound there are several difficulties which make it impossible to
following lines using Cionn inta~tinnlis and Phallwia ntammillata as
experimental animals.
(a) Mamrntilian chorionic gonadotrophin was injected into test
animals and distillod water into oolitrols. Itegardless of the site of
injection the gonadotrophin stirnulatod diecharge of gametes about 20
hours later (see also Carlisle, 1964, with reference to these experiments).
If the heart had previously been destroyed and the blood drained, this
response (shedding of gametes) only occurred if injection waa directly
into the neural region but not if injected into the gonad or elsewhere in
the body. These experiments could be interpreted to mean that the
hormone induces gamete release but does not affoct the gonads directly
and probably only through the intermediary of the nerve ganglion.
(b) The nerves between the ganglion and the gonads were sectioned
and gonadotrophin was then injected into the body as above. Under
these circumstances there was no positive response of gamete release
but if the gonadial nerve and ganglion were left intact and all other
nerves from the ganglion were severed, then there was a response of
gamete release. Furthermore if the ganglion was left intact but the
neural gland wa8 destroyed there was still a positive response of gamete
release when gonadotrophin was injected into the ascidian. These
experiments can be interpreted to mean that mammalian chorionic
gonadotrophin stimulates the nerve ganglion which in turn stimulates
release of gametes.
(c) When instead of using chorionic gonadotrophin a highly concentrated extract of ascidian neural gland was injected (about 100
glands per injection dose) a similar positive response of gamete dkcharge was elicited.
(d) Gametes were also released when an ascidian was fed with a
suspension of gametes of its own specie8 but not if fed with gamete?
from another species of ascidian.
From these experiments Carlisle concluded that the neural gland
functions in the release of gametes in the manner suggested by HUUR
(loc. cit.) but through the following chain of events:
Gametes in the inhalant water current are taken into the gland.
Gametes stimulate the gland to secrete B hormone.
The hormone excites the ganglion.
Nervous pathways from the ganglion through the gonadial nerve
stirnulate the release of gametes.
While the experiniental techniques used by Carlisle appear to have
been sound there are several difficulties which make it impossible to