239 
In an addendum to the paper recently published by me (15) I 
stated that from preliminary experiments with the ISRAEL-PAPPENHEIM 
stain recommended to me by Dr. BucKMASTER it was apparently pos- 
sible to detect the presence of haemoglobin in the cytoplasm of the 
active gland cells. This ISRAEL-PAPPENHEIM stain (made by mixing 
6 gms. of Rose Bengal, 2 gms. of Orange G and 1 gram of Aurantin 
together and dissolving until the solution is saturated in a warm mix- 
ture of 10 vols. of distilled water, 1 vol. of glycerine and 1 vol. of 
absolute alcohol; the fluid should be quite transparent before using) 
colors haemoglobin a coppery-yellow hue, quite distinct from the red 
coloration of other tissues in the preparation, and so far as I know, 
it constitutes the only available method of ascertaining the exact 
distribution of haemoglobin in thin sections of tissue. Before visiting 
Plymouth I decolorized in acid three of my slides of the gland of 
Gobius minutus (the cells of this gland — fixed in ZENKER — exhibiting 
the numerous vacuolar spheres portrayed in Fig. 35, pl. V of my 
previous paper and which I therefore concluded to have been in a 
very active condition when fixed), graded the sections down to water 
and stained for five minutes or so in the IsRAEL-PAPPENHEIM stain. 
On remounting these sections in balsam I clearly observed that both 
the haemoglobin of tbe blood corpuscles and the substance of the 
gland cells (including nuclei) were stained a copper color, the rest of 
the tissues being a dull red. I showed these slides (which I still 
possess of course) to Dr. BUCKMASTER and others and they certainly 
appeared to support the conclusion that the cytoplasm of the gland 
cells contained diffuse haemoglobin. 
On visiting Plymouth I decided to confirm these observations if 
possible. I fixed in absolute alcohol the active glands of Pollack 
which had been weighted 16 hours (two fish), 7 hours (one fish) and 
6 hours (at least three fish) and of two Congers which had been sunk 
thirty fathoms for 5 hours. I also fixed in Mann’s fluid the active 
gland of a Pollack weighted 6 hours and in absolute alcohol the 
presumably inactive glands of two unweighted (control) Pollack and 
two Congers. On making unstained thin sections of these glands, grad- 
ing them down to water and staining them with IsRAEL-PAPPENHEIM 
for periods varying from five minutes to half an hour and longer (in 
some cases all night), I confess that I failed to detect a trace of the 
copper color in the cytoplasm of the gland cells. I found that the 
stained haemoglobin was most distinct from the rest of the tissue 
substances immediately after washing the stain off the slide in water: 
mounting in balsam hid the distinctive color of the haemoglobin in 
