650 A. F. Goldfarb 
If it can be shown in these three series (1) that all nerve cells 
of the cord supplying the hind limb were destroyed, (2) that other 
motor nerves from regions in front have not grown or connected 
with those in the paralyzed limbs, (3) that the nerve cord itself 
has not grown into the lumbar region to supply the limbs with a 
newset of nerves, it follows that in the adult Diemyctylus viridescens 
the missing parts of the limb may be restored without the aid or 
stimulus of motor nerve impulses. In the above three series, 
whether the limbs were completely or only incompletely paralyzed, 
or whether paralysis occurred before or after amputation, new limbs 
regenerated in nearly every instance. 
Lumbo-sacral Plexus Destroyed—Limbs Paralyzed Completely 
Many of the operated animals were studied in serial section. 
The tail, both fore and hind limbs, and the lumbar and thoracic 
regions of the body were preserved in Hermann’s platinic chloride, 
containing 4 per centosmic. In some instances corrosive acetic was 
used. Apathy’s silver nitrate and Bielschowsky’s silver methods 
were tried with very uncertain results. As is well known the osmic 
content of the Hermann mixture stains the myelin of medullated 
nerve fibers intensely black. The myelin stains deeply even after 
it has broken down in the familiar Wallerian degeneration and 
until all the fatty globules thus produced have disintegrated or 
been absorbed completely, so that the progress of the degener- 
ating and regenerating nerve fibers are readily studied. Surround- 
ing tissues are likewise stained a pale yellow-brown, sufficiently 
intense in most cases for general use. Sometimes Delafield’s 
Hematoxylin was used to emphasize certain structures. While 
in general Hermann’s fluid gives excellent results both as a fixing 
and a staining solution, it is not always to be depended upon, 
especially when large objects are used. ‘The platinic chloride may 
penetrate the inner regions more rapidly than the osmic, preventing 
the fatty tissue from taking the characteristic stain. 
The following animals include those from which at least the 
8 For this explanation I am indebted to Dr. O. S. Strong. 
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