524 ON THE REPRODUCTION OF THE NERVES. 
weeks, but in the eighteenth it was not quite restored. This is 
the usual course in one case. He remarked that the ends of the 
nerves united by granulations. Incised and partially divided 
wounds healed like those where the division was complete, and 
the functions suffered little from them. If a portion of nerve was 
removed, the nerve healed in the usual way : the long time which 
the healing required has been the cause of many persons doubting 
its real occurrence. Mr. Swan even doubted himself the resto- 
ration of the functions, until the following experiment convinced 
him of the accuracy of the fact. A portion of nerve leading to 
the leg was removed from a horse which had been lame for two 
years. For six months from the time of the operation, the animal 
was quite healthy, but soon after it again became lame. On 
killing the horse afterwards, it was found that the nerves had 
united. In another experiment, quite new nerves were found, 
one which led to the ham, and another to the part where the 
fibular nerve is situated in the human subject. Ligatures pro- 
duce the same effect as the division of the nerves. On the ap- 
plication of a ligature on the nerve, coagulable lymph is thrown 
out ; and when the ligature comes away, the nerve re-unites and 
the functions become restored. Richetand confirmed this fact 
by experiment. Soemmering and other anatomists have also 
advanced the opinion, that the substance of the brain may be 
also regenerated. 
Flourens, in his experiments on the nervous system, has 
denied the accuracy of this opinion. The error, he thinks, has 
arisen from the great expansion of the cerebral substance after 
the infliction of wounds on it. This swelling after a few days 
disappears, and then it may be very clearly seen that no repro- 
duction has taken place. The functions, it is true, become 
restored, but this does not depend on the reproduction of the 
parts. Experiments have also been tried on the reproduction of 
the spinal marrow. Arnemann divided the medulla spinalis of a 
dog in the lumbar region, and, after the lapse of eight weeks, 
the dog was able to walk. On killing the animal, it was found 
that the divided parts had re-united, but by what he conceived to 
be the nervous substance. 
Lancet, vol. xi, p. 764. 
