ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
699 
posed of indigo-carmine 8 grm., borax 8 grm., and distilled 'water 
100 ccm. The section to be stained is left in the fluid for 15 minutes, 
then plunged in a saturated solution of oxalic acid for 10 minutes, 
washed in distilled water, dehydrated with absolute alcohol, cleared in 
pure xylol, and mounted in benzole balsam. Essential oils should be 
avoided as they appear to oxidise the indigo-carmine, and cause the 
stain to fade. 
For the hardening of the tissues preparatory to cutting, small 
portions should be half an hour in a saturated solution of carmine sub- 
limate, or 5 days in Erlicki’s fluid, or 24 hours in a 1/5 to 1/3 per 
cent, solution of chromic acid, 5 hours in a saturated solution of picric 
acid, or 2 to 5 hours in 1 per cent, solution of osmic acid. They 
must then be washed in distilled water, and put in 50 per cent, 
alcohol for 2 hours, in 70 per cent, for 24 hours, and finally in 95 
per cent. The pieces may be imbedded in mucilage and sectioned 
in the freezing microtome, or by the chloroform method in paraffin. 
The great value of these preparations lies in the fact that haemoglobin is 
stained grass-green or greenish-blue, while other proteid elements are 
coloured red, save a few about which there can be no mistake. 
Alum-haematoxylin, in which ammonia-alum is dissolved to satura- 
tion, and Czokor’s alum-cochineal were also of great value in the study 
of the haematoblasts of the larvae of Amblystoma. 
Cover-glass preparations of blood were fixed either in the fumes of 
osmic acid (1 per cent, for 2 hours), or by a saturated solution of 
corrosive sublimate or picric acid, or by Erlicki’s fluid. The fixation 
was completed as usual with alcohol, and the various dyes already 
mentioned were used for staining the preparations. 
Examination of Teleostean Ova.* — In his study of the mesoderm 
of Teleostean fishes Mr. E. R. Boyer made use of the oviparous Cyprino- 
dont Fundulus heteroclitus. The ova were killed at intervals increasing 
from one hour in the younger to eight hours in the older stages. The 
killing reagents used were Perenyi’s fluid, Kleinenberg’s picro-sulpliuric 
mixture, and a solution of 0*25 per cent, osmic acid, followed by 
Whitman’s modification of Merkel’s fluid. The ova were next carried 
through grades of alcohol to 90 per cent. Those preserved with 
Perenyi’s fluid proved to be most satisfactory in the earlier, and those 
with Kleinenberg’s mixture in the later stages. The best staining 
results were obtained by the use of Kleinenberg’s hsematoxylin in toto 
for 20 to 24 hours, and decolorizing with 70 per cent, acidulated 
alcohol for about 2 to 4 hours. With osmic material, however, the 
best results were attained by the use of Czokor’s cochineal for 10 to 
12 hours. The embryos were removed from the yolk under the dis- 
secting Microscope, dehydrated, penetrated with clove or cedar oil, 
followed with paraffin at a temperature of 55° C., imbedded in paraffin 
in the usual way and cut into sections by a Thoma or a Cambridge 
rocking microtome. 
Study of Germinal Layers of Petromyzon.t — Mr. S. Hatta hardened 
the eggs and larvae of Petromyzon partly in kleinenberg’s picro-sul- 
* Bull. Mus. Comp. Zool., xxiii. (1892) pp. 93 and 4 (8 pis.). 
t Journal Coll. SSci. Imp. Univ. Japan, v. (1892) p. 130. 
