PHYSIOLOGY OP LAMELLIBEANCH BLOOD-COEPUSCLES. 609 
A pipette with a jagged or sharp point should not be used, 
as this tends to cause agglutination of the corpuscles. 
By this method I have obtained as much as 20 c.c. of blood 
from a large specimen of Cardium norvegicum. 
Fixing and Staining Methods, 
By far the most satisfactory results were obtained by 
simple fixation with corrosive sublimate, and staining with 
aqueous eosin and methylene blue. 
A drop of blood is allowed to fall on a slide from the 
collecting pipette, and is then left in a moist chamber for from 
half an hour to an hour to allow the corpuscles to expand. 
Two or three drops of a saturated solution of corrosive subli- 
mate in sea-water should then be added, and left for five 
minutes. This is drained off, and the slide washed in 90 per 
cent, alcohol. After this the slides may be placed in water 
for a few minutes, and then stained for some time in a dilute 
aqueous solution of eosin ; this is washed off, and Loefflei*’s 
methylene blue, diluted 1 in 100, is added, and left for from 
one to two minutes. The slide is finally washed in distilled 
water, allowed to dry (not blotted), and mounted in xylol 
balsam. 
Almost equally good results were obtained by fixation with 
osmic acid, but no other fixatives employed were really 
satisfactory. No variety of the Romanowsky stain gave such 
good results as treatment with eosin and methylene blue, 
one after the other. Haematoxylin stained the nuclei well, 
but interfered with the differentiation of the eosinophil 
granules. 
Treatment of the fresh blood with 1 per cent, acetic acid 
and methylene green differentiates the nuclei of the corpuscles, 
but fixation is not sufficiently rapid to enable the corpuscles 
to be examined in the expanded condition. 
Sections of the tissues showing wounds, etc., were fixed in 
corrosive sublimate, and stained with Ehrlich’s haematoxylin 
and erythrosin, or van Gieson’s stain. 
