AUTHOR’S ABSTRACT OF THIS PAPER ISSUED 
BY THE BIBLIOGRAPHIC SERVICE, MAY Il 
THE THORACIC TRUNCUS SYMPATHICUS, RAMI 
COMMUNICANTES AND SPLANCHNIC NERVES 
IN, THE ‘CAT 
S. W. RANSON anp P. R. BILLINGSLEY 
From the Anatomical Laboratory of the Northwestern University Medical School! 
NINE FIGURES 
In other papers of this series, which appear on the preceding 
pages, we have dealt with the cervical portion of the sympathetic 
trunk, the superior cervical ganglion, and the branches which it 
gives off. We come now to a consideration of the thoracic por- 
tion, its rami communicantes and the splanchnic nerves. Our 
preparations were obtained from cats because most of Langley’s 
observations were made on these animals and we wished to com- 
pare our results with his. 
The work was started with the hope of throwing some light on 
the origin of the various types of fibers in the splanchnic nerves. 
Since these fibers are known to belong for the most part to seg- 
ments caudad to the fifth thoracic, we began by studying the 
rami from the sixth to the thirteenth thoracic nerves and the 
corresponding portions of the trunk. It was only after the study 
of this material had shown that many significant details con- 
cerning this nerve trunk had never been described that we began 
the study of it in the first five thoracic segments. Hence the 
material representing this part was taken from different cats 
than those in which the sixth to the thirteenth thoracic segments 
were studied. But in each case a sufficient number of specimens . 
was secured to make sure that the peculiarities encountered at 
different levels were characteristic for those levels. In all 
nearly twenty cats were used, exclusive of those on which opera- 
tions were performed to produce the degenerations to be reported 
in the following paper. 
1 Contribution No. 58, February 15, 1918. 
405 
