238 
24 hours and at least four Siphonostoma were weighted for 6 hours, 
the glands of these fish being fixed, stained and sectionized in the 
same way as those of the Pollack. 
Six Congers, three Wrasse (Labrus maculatus) and six Siphono- 
stoma were also lowered in closed weighted baskets to a depth of 
thirty fathoms off the Eddystone lighthouse and allowed to remain 
there for 5 hours; the glands of these fish were sectionized in the 
manner already described and compared with similarly prepared sections 
of control fish not subjected to this increase of pressure. I may also 
recall the fact (15) that at Plymouth two years ago I lowered from 
fifteen to twenty Gobius paganellus to depths of 5, 10, 15 and 30 
fathoms for periods ranging from half an hour to two and a half hours 
and was also unable to detect haemolysis in any of the glands sectionized. 
From the above evidence it seems to be fairly certain that haemo- 
lysis of the blood does not occur in connection with the activity of the 
gas gland and rete mirabile. To what then is due the appearances 
of haemolysis in the slides prepared from the material collected by 
me at Naples? It is hard to believe that these appearances are due 
to faulty fixation, since there is no evidence of this in the tissues 
other than the blood‘), and the glands were fixed in ZENKER or cor- 
rosive acetic in probably the same way as the more recent glands, i. e. 
the bladder was probably pricked and immediately filled and distended 
with the fixative. It is however possible, and it is the only suggestion 
which occurs to me, that the glands showing this haemolysis are some 
of a certain number which were not fixed quite in this way, being 
fixed for the first half hour from the outside of the bladder only (the 
fixative being simply poured on to the exterior) and only subsequently 
being transferred from the bladder wall and completely fixed in a large 
bulk of the fluid. Since during the first half hour of fixation, the 
fixative would have to penetrate through the muscular layers of the 
bladder wall before reaching the gland, it is possible that the weak 
acetic acid constituent of the fixative penetrated sooner than the other 
constituents and dissolved out the haemoglobin from the corpuscles 
before these became fixed as a whole. But I have no evidence for 
this supposition, not having had time to put it to the test at Plymouth. 
3) Is there any evidence of the gas gland cells ab- 
sorbing dissolved oxyhaemoglobin from the blood? 
1) I exhibited these slides at the last Conversazione of the Royal 
Society of London, on which occasion they were examined by several 
eminent histologists. 
