———— 
WILLARD: CRANIAL NERVES OF ANOLIS CAROLINENSIS. 21 
The projection plots were made from camera drawings magnified 
37 diameters and, except in regions of greatest complication, each 
nerve was projected accurately throughout its entire course. In a 
few cases some of the nerves are displaced a little from the position 
they really occupy in the middle of their course in order to avoid too 
great confusion of lines. Of course the essential points such as central 
and peripheral endings and relationship of branches given off in the 
intermediate course are strictly adhered to. 
Even after the most careful study of serial sections and reconstruc- 
tions, one is likely to fall into error unless the work is supplemented 
by free-hand dissections. This is particularly true in case of very 
small branching rami or fine plexuses. Animals that are small enough 
to be practicable for sectioning are generally too small for entire dis- 
sections, but by the following method it was possible to make accurate 
and fairly complete dissections of the head: — the integument of the 
part wanted for dissection was carefully removed to avoid cutting any 
of the underlying muscles. Then the animal was put into the Vom 
Rath fluid, as for sectioning, but treated a shorter time (24 to 36 
hours). This decalcifies sufficiently well, hardens the muscles and 
leaves them well defined because of a slight shrinkage; it also hardens 
and blackens the nerves. Instead of further hardening in alcohol, the 
specimen was washed out in water and put into a mixture of alcohol 
and glycerine. It was afterwards dissected in water under a lens. 
For best results, however, it should be dissected soon. Although the 
whole muscle is much darkened, there is contrast enough between it 
and the nerves to allow the identification of the finest branches of the 
blackened nerves. The muscles are also more or less brittle, whereas 
the nerves retain their characteristic toughness. As the dissection 
progressed portions were removed and cleared for permanent mounts 
in balsam. I consider the making of balsam preparations a very 
valuable part of the technique of this work, for in no other way can 
the fiber course in the finer anastomoses be made out. For ascertain- 
ing the courses of nerves and for topographical relations this short 
Yom Rath method is a valuable adjunct and the two methods — 
sections and dissections — were constantly used together. 
For the central relations I found that properly prepared Weigert 
’ preparations gave more satisfactory results than the Vom Rath, but 
the latter method allowed the roots to be followed well into the brain 
and in some instances served even there better than the Weigert. 
Portions of the courses brought out by one method overlap those by the 
other, so there could be no chance 6f error in combining these two 
methods of study. 
