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MULTIPLE NEUROMATA OF THE CENTRAL NERVOUS SYSTEM. 723 
dogs, removed the whole lumbo-sacral cord and spinal ganglia, thus including the 
nuclei of origin not only of the sciatic nerve but also of the crural and obturator nerves, 
and three months later he found no regeneration. The sheath of Schwann cells had 
arranged themselves in protoplasmic bands, but these contained neither axis-cylinder nor 
myelin. ‘There were present fine axis-cylinders, so numerous that they seemed to speak 
in favour of autogenous regeneration, but Lucaro assumed that they were sympathetic 
fibres. In one dog, therefore, he completely severed the central end of the sciatic from 
its connections with the sympathetic nerves, but he left the sympathetic attachments to 
the obturator and crural nerves. By means of Cajal’s reduced silver method, a hundred 
days after the operation, he was able to demonstrate large numbers of axis-cylinders in 
the obturator and crural nerves, but none in the sciatic nerve. 
Mopena (1905), Munzer and Fiscuer (1905), Von Krassin (1906) and Busta (1906), 
must be mentioned amongst those whom Berur’s results stimulated to an experimental 
endeavour to solve this difficult question. Moprna and Besta relate the development 
of the new fibres to the Schwann cells, but insist on the necessity of the central 
influence for their complete differentiation. The others are centralists. Von Krassin 
used the intravital methylene-blue method of Ehrlich, up till then scarcely applied in 
the study of regeneration. 
Marinesco (1905) performed section of the sciatic and crural nerves both in newly- 
born and adult animals. He states that reunion of cut ends is not essential to regenera- 
tion, and that this can arise in both central and peripheral ends through the prolifera- 
tion of the sheath of Schwann cells. The details are those which we have seen in Von 
Bunener’s work: the formation of fusiform cells and protoplasmic bands with at first 
fine, almost invisible, lines within the cell protoplasm ; later, thicker black lines stained 
with Cajal’s silver method and the development of the myelin sheath and sheath of 
Schwann. An illustration given by Marinzsco in this paper is a very striking proof of 
the spiral formations having arisen within cells. Around an old axis-cylinder of the 
central end coils spirally a thin fibre, and the components of the spiral are within cells 
in the protoplasm of which they have developed: the cells are arranged transversely 
to the old fibre. 
In the following year, however, Marinesco and MINnEa carried out a new series of 
experiments which led Martnesco to change his views on autogenous regeneration. 
Both authors look upon the cells within which the axis-cylinders were thought to have 
developed only as an advance guard to provide for the nutrition and orientation of the 
new fibres. They attribute the young fibres to outgrowths from the central end, the 
axis-cylinder of which, by longitudinal dissociation, has formed fibrils each of which 
terminates in a céne de croissance. Collateral division of the central end axis-cylinder 
may also take place, and such collateral fibres tend to assume a spiral direction round 
the old fibres. These authors part company from Casat in attributing no phagocytic 
role to the proliferated cells, which they term cellules apotrophiques. In a further 
series of experiments Marinesco grafted small pieces of nerve into animals of the same 
