1233 



taken should be siitïïcieiit to sliow degeneration (periplierically of 

 the place where the cut was made) in Ag — impregnated prepa- 

 rations of the nerve tibres that had been cut off. Tkllo ') gives 

 further details about the time of the appearance of degeneration 

 that can be shown morphologically in the nerves peripherically of 

 the place of the section. 



The plexus brachialis of the cat is generally formed by the 

 ventral branches of the first thoracic ner\e (I have sometimes, how- 

 ever, observed a fine branch from the second thoracic nerve) and 

 the last three cervical nerves. As is shown above, one segmental 

 nerve cranially and one caudally of those that generally form the 

 plexus had thus been caused to degenerate. This was done to ensure 

 complete certainty that, even if some branch might possibly come 

 from these contigiions nerves to the anterior extremities, all the 

 spinal nerves there would have undergone degeneratioji. After the 

 animal had been killed, the results of the operation were carefully 

 verified, and they were found to he good. The animal in question 

 had no branch from the second thoracal nerve to the plexus brachialis. 

 After the blood had been removed by injecting physiological solution 

 of common salt from the heart, the anterior extremity on the side 

 where the animal had undergone the operation was fixed by inject- 

 ing a twenty per cent solution of formaldehyd from the a. axillaris. 

 The extremity was kept for some time in formalin. The mm. interossei 

 were impregnated according to my modifications') of Biklschowsky's 

 method of silver impregnation. 



It was clear from sections of the impregnated muscles that all 

 the myelinized nerves, both the motor ones and the sensory ones, 

 had undergone degeneration. On the other hand 1 found quite a 

 number of intact non-medullated nerves. These intact nerves were 

 found in the preparations partly together with bundles of degenerated 

 spinal nerves and partly along vessels. I was able to follow a large 

 number of the intact non-medullated nerves out to their terminal 

 organs. These terminal organs were situated partly on ordinary 

 cross-striated muscle fibres and partly on muscle fibres in muscle- 

 spindles. I shall give a more detailed account of the sympathetic 

 terminal organs in muscle spindles in a later and more complete 



^) Tello, F. Degeneration et regeneration des plaques molrices après la section 

 des nerves. Travaux dia laborat. de rech. bioiog. publ. par S. R. Gajal, Tome V. 

 1907. 



*) Erik Agdur: Ueber Sliickfarbung mit Bielschowskys Silberimpragnations- 

 melhode. — Einige Modifikalionen. Zeitschr. f. wiss. Mikrosk. u. f. mikrosk. 

 Techn., Bd. 34, 1917. 



