1228 



vation might be of a tonic or of a trophic nature. This question 

 however is to be answered by means of plijsiological experiments, 

 and the investigation of it therefore must be left to practised phy- 

 siologists, and need not to be discussed in this paper. 



The sympathetic nature of these "accessory" fibres could be shown 

 afterwards by cutting the eye-muscle-nerves ftrochlearis, oculomotorius) 

 directly after they have left the mid-brain, which caused the sensible 

 and motor nerve-fibres to degenerate. The accessory non-medullated 

 nerve-ilbres however and theii- end-oi'gans on the muscle-fibres 

 remained unaltered (Bokkk, 1911, 1916), which could only be ex- 

 plained by admitting, that they are transferred to the eye-muscle 

 nerves by way of the sympathetic branch, which reaches the orbita 

 along the arteria opthalmica from the plexus caroticus, so that they 

 were not dissected when the eye-muscle nerves wei-e cut directly 

 behind their place of origin from the brain-stem. 



Experiments, in which a series of spinal nerve-roots of the cat 

 were cut, made in collaboration with Prof. Magnus, hoNyever did 

 not give cleai- and unquestionable results, which perhaps may find 

 its explanation in the fact, that the elements of the sympathetic 

 nervous system genei-ally take the stain far less readily than the 

 other nervous elements. A negative result of a staining reaction is 

 therefore in no case e\ incing for the non-existence of these sympa- 

 thetic elements. Afterwards similar experiments have been executed 

 with better results, and Dr. Agduhk, who has a communication on 

 this subject appearing in this numbei' of the Proceedings, obtained 

 the same definite and positive results with the muscles of the extre- 

 mities as those, which we are going to describe for the intercostal 

 musculature. 



The experiment, the result of which we are going to describe 

 here, was executed by one of us (D. de B.) in the following manner : 



In a cat were extirpated at the right side of the medulla spinalis 

 inside the dura mater a series of 4 consecutive ganglia spinalia with 

 simultaneous section of the corresponding |)OSterior and anterior 

 roots. This was done on the 15^'^ of February. The wound healed 

 per primam, the animal remained healthy. A month afterwards 

 (IS**^ of March) the animal was killed by chloroform, and the blood- 

 vessels were cleaned thoroughly by rinsing them with Ringer's fluid. 

 After that the thoracic wall was rinsed with a neutralised solution 

 of formalin (12 7o). '^»d preserved in formalin 127», alcohol 60 7o- 

 The autopsy siiowed that the posterior and anterior roots of thoracalis 

 VI, VII, VllI and IX with the corresponding ganglia spinalia were 

 cut thi-ough. The most reliable results therefore were to be expected 



