DEGENERATION AND REGENERATION OF NERVE FIBERS 499 
tion, and with them only from the histological standpoint, little 
if any information would have been secured by electrical stimu- 
lation of the stumps. The omission of these physiological tests 
of regeneration was the more excusable, since, as has been men- 
tioned, the majority of the autopsies were complete before it 
was determined to extend the scope of the study from the degen- 
erative changes to include the regenerative processes as well. 
With two exceptions the wounds healed by primary intention. 
In Dog 1m the cutaneous stitches came out on the fourth day, 
but this dog was killed on that same day and the deeper parts 
TABLE 1 
NUMBER OF |DAYS BETWEEN OPERA‘VION AMOUNT OF NERVE WHETHER SUTURED OR 
EXPERIMENT AND AUTOPSY REMOVED ALLOWED TO RETRACT 
I 1 None Sutured 
aT 35 None . Sutured 
Ill 4 None | Sutured 
IV | 8 None | Sutured 
V 14 | None | Sutured 
VI | 19 | None Sutured 
VII 34 | 1 cm. | Retracted 
VIELE | 34 | None | Sutured 
IX 25 | None | Sutured 
x 25 | 1 cm. | Retracted 
Dall 1 | None Retracted 
XII , | None | Retracted 
Guat 3 | None | Retracted 
XIV | 4 | None Retracted 
of the wound were free from infection. Dog rx became infected 
and was discarded. Dog 1 died about twenty-four hours after the 
operation probably from late effects of the anaesthetic. The 
other dogs remained in excellent health until they were killed. 
Table 1 shows what experiments were made. 
The tissue was prepared by the pyridine-silver modification 
of Cajal’s method, the steps of which are as follows: The nerve 
is placed for forty-eight hours in absolute alcohol to which has 
been added 1 per cent of strong ammonia. The pieces are then 
washed for two minutes in distilled water and transferred to 
pyridine for twenty-four hours, after which they are washed 
in many changes of distilled water for twenty-four hours. They 
