314 ; General Notes. [ March, 
laries, may be easily traced by this method, as was first pointed 
out by E. Ray Lankester.? 
METHODS oF INJECTING ANNELIDs (Maurice Jaquet).?—For an- 
nelids with dark tissues like Hirudo, a light-colored (white or 
yellow) injection-mass should be employed, while for transparent 
animals dark colors are preferable. Chrome yellow serves asa 
good coloring substance. It is easily obtained by mixing solu- 
tions of bichromate of potassium and acetate of lead. A copious. 
yellow precipitate is formed, which should be washed on the filter, 
and then exposed to the air until nearly dry. The pigment, after 
being reduced to a pulp-like state, is added to an ordinary aque- 
ous solution of gelatine; and the mass is then filtered warm 
through linen. If the injection-mass is to be blue, then the gela- 
tine may be dissolved directly in liquid Prussian blue, and the 
mass filtered througn the paper: 
As a rule, annelids must be killed before they can be injected. 
Chloroform and alcohol are the means commonly employed in 
killing for the purpose of injection; fresh water may also be used 
for some marine species. A leech, for example, is placed in 
should be allowed to remain in the water from one to two days 
before attempting to inject it. 
The simplest and most convenient form of syringe consists of 
a glass tube drawn to a fine point at one extremity, and furnished 
at the other with a rubber tube. Preparatory to injecting, the 
glass should be plunged in warm water for a few moments; then, 
after expelling the water, it may be filled with the injection-mass 
by sucking the air from the rubber tube. If the injection-mass is 
_ turned into the large end of the glass, it may happen that gran- 
ules are introduced which are large enough to obstruct the nar- 
row passage of the small end. After inserting the cannular end 
_ in the vessel, clasp both with the forceps, and then force the in- 
jecting fluid, by aspiration through the rubber tube, which is 
held in the mouth. When the operation is completed, place the 
animal in cold water, in order to stiffen the injected mass. 
Aw InjEcTION-Mass TO BE USED Corp.—3 
l PS 
B ( i solution) I part. 
Gum arabic . eag parts, 
ok The solutions are best made in hot water. The mixture of the 
solutions gives a gelatinous mass that is nearly insoluble in water. 
: and then pressed through linen. A thick fluid is thus obtained, 
_ which, with the addition of a little more water, must again be 
e 3 
? Mitth, a. d. Zoöl., Station z, Neapel, vi, H. 3, p- 298, Dec. 1885. 
_-*A.K. Bjelousson, Arch. f. Anat. u. Phys. (Anat. Abth.), 1885. H. 5 and 6, p 379° 
The mass is broken up into small pieces and a little water added, | 
Cl ew A 
