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of absorption of the dissolved oxyhaemoglobin taking place, and the 
suggestion (not statement) has been made (WoopLAND) that the 
ISRAEL- PAPPENHEIM stain for haemoglobin demonstrates the actual 
presence of diffuse haemoglobin in the cytoplasm of the gas gland 
cells. Further, as already mentioned, it is supposed that the gas 
gland cells split off the oxygen from the haemoglobin and cause the 
former to appear in the cytoplasm as bubbles of gas (BYkKowskI1, 
NusBAum, Reis) which are eventually pumped by the cells into the 
bladder cavity, the granular matter present in the last being supposed 
to result from the bursting of these gas bubbles, i. e. mechanical 
disintegration of cytoplasm. Finally a theory has been proposed 
(WOODLAND) concerning the probable function of the rete mirabile 
duplex. In brief, this remarkable structure is supposed to exist for 
the purpose of enabling the lysin, secreted by the gland cells, to act 
upon the arterial blood before it comes into contact with the gas 
gland, so that by the time the blood reaches the gland the oxy- 
haemoglobin shall be already dissolved in the plasma and so available 
for abstraction by the gland cells. On this view the gland pours the 
hypothetical lysin (JAEGER’s “toxin”) into the blood, which, returning 
from the gland, subsequently traverses the venules of the rete; during 
its course in the rete the toxin diffuses from the venules into the 
adjacent arterioles where it produces haemolysis of the arterial blood, 
a process which effects the solution in the plasma of a quantity of 
oxyhaemoglobin by the time the arterial blood reaches the gas gland. 
~~ Evidence adduced in favour of this view is the possible fact (only 
stated as being probably a fact) that examination of serial sections 
through a rete associated with an active gas gland reveals erythro- 
cytolysis as occurring in the venous blood of the rete and gland and 
in the arterial blood leaving the rete to supply the gland but 
apparently not in the arterial blood entering the rete. 
The reader is now in possession of the main facts and suggestions +) 
which have been put forward concerning the physiology of the gas 
gland and rete mirabile of teleosts and will therefore be able to 
appreciate the significance of the following description of the results 
obtained from numerous experiments recently conducted by me at the 
Plymouth Marine Biological Station for the purpose of confirming or 
disproving the general theory above outlined. Before stating these 
results I wish to express my indebtedness to Professor J. P. HILL, 
1) For a more complete account of the subject see the paper 
already referred to, 15. 
