-16- 
Regardless of the care exercised, a coating gradually accumulates 
on the inside walls of the syringe, and finally interferes with the 
passage of semen. This coating can be removed with a piece of wire 
0»002 inch in diameter slightly bent at the end. Flakes that are too 
large to pass through easily can usually be removed by drawing back the 
plunger slowly so that water passes around and behind them and then push- 
ing out very suddenly so that they will be carried withthe stream of 
water. Several repetitions of this procedure will usually clear the 
barrel. The glass tip can be cleaned by dipping in a hot solution of an 
alkali such as sodiiim hydroxide or common lye, which dissolves the depos- 
its; however, the alkali must be thoroughly rinsed out before the syringe 
can be used again, "hen using alkali it is best to withdraw the plunger 
15 to 20 mm. and leave the tip full of air, then to draw in a small quan- 
tity of the hot alkali. Later the alkali can be forced out and the rins- 
ing done without any contact with the plunger. 
The plastic syringe need be cleaned only when it is to be stored or 
when the plunger becomes too tight. Cleaning is simple. The tip etnd plunger 
are unscrewed, and water is drawn in and out with the plunger with such 
force that usually all obstructions are easily rinsed out. 
Sterilizing the Syringe 
Fnen a quick change is made from one genetic type of sperm to another, 
it is necessary to sterilize thd syringe. The glass syringe is sterilized 
by rinsing it thoroughly and then dipping it in boiling water deeply 
enough to submerge part of the pencil as well as the exposed part of the 
glass tip, so that the inside end of the tip also becomes heated. If several 
syringes are available, a fresh one oeua be employed for each kind of drone 
used in a single day. The plastic tip is sterilized by quickly drawing 
in and expelling 95 per cent ethyl alcohol, and then thoroughly rinsing 
with water immediately, because Lucite is slowly soluble in alcohol. 
ESTIMATING THE NUMBER OF SPERMS 
One criterion of successful insemination is the number of sperms that 
reach the spermatheca. A fairly good estimate can be made by the following 
method : 
Items of equipment needed include a counting chamber such as is used 
to count blood corpuscles, a 50-cc. burette, a medicine-dropper pipette, a 
small glass dish, a pair of sharp-pointed forceps, and a dissecting needle. 
The pipette should have an inside diameter of about 1 mm. at the tip. For 
the glass dish an individual saltcellar almost as deep as wide, having a 
capacity a little over 10 cc, and having a rounded bottom somewhat smaller 
than the diameter of the rim, has been found to be just the right size and 
shape. 
To dissect out the spermatheca one must tear off the last segment of 
the abdomen by grasping the last ventral plate with forceps. The spermatheca 
is usually found imbedded in the tissue inside this removed segment. It 
is a sphere about 1 mm. in diameter and appears rough and white because of 
the network of tracheae which covers it completely, ^''hen the tracheae are 
