19 
A NOTE ON THE APPLTCATLON OF GIEMSA’S ROMAN- 
OWSKY STAIN TO THE BLOOD AND TISSUES OF 
MARINE INVERTEBRATES. 
By G. HAROLD DREW. 
Beit Memorial Research Fellow. 
This method is especially applicable to the blood and body fluids of 
Invertebrates in which true clotting does not occur, and in which the 
proportion of proteid substances in the serum is not high. 
In the case of marine animals, dry smears of the blood cannot be 
successfully obtained, as the quantity of salts in solution in the blood 
prevents that almost instantaneous drying which is necessary, and also 
gives rise to the foi'mation of crystals which causes much distortion of 
the organised elements of the blood. Accordingly films of blood must 
be fixed while wet, and as Giemsa’s stain gives, the most satisfactory 
results after Sublimate fixation, the following method was employed : 
1. The blood is withdrawn from the animal with a fine pointed 
glass pipette, the end of which has been carefully rounded in the flame, 
and two or three drops are allowed to run on to the middle of a slide. 
It is essential that both pipette and slide be absolutely chemically clean, 
and should show no scratches or rough surfaces. 
2. The blood is allowed to remain on the slide for two or three 
minutes to allow the corpuscles to settle on the glass, and then an equal 
volume of a saturated solution of Corrosive Sublimate in sea water is 
added, care being taken that the fluid on the slide spreads as little as 
possible. By this means the corpuscles are partially fixed, and are 
found in a thin film adhering to the glass. Proteid substances in the 
blood are precipitated, but if not present in large quantities the pre¬ 
cipitate does not interfere with the preparation, as little of it adheres to 
the slide. 
\ 
3. After ten minutes, the slide is placed in Schaudinn’s solution 
(saturated solution of Corrosive Sublimate two parts, absolute Alcohol 
2—2 
