THE NERVOUS SYSTEM 447 



the muscle cells. Satisfactory differentiation between efferent 

 terminals and afferent terminals in heart and in smooth muscle has 

 not yet been made. 



In organs whose parenchyma is made up of glandular epithelium, 

 the sympathetic nerves terminate mainly in free endings which lie 

 in the cement substance between the cells, thus coming in contact 

 with, though not penetrating, the epithelial cells. 



A. 



b ■ „ 



b 



Fig. 314. — Nerve Endings on Smooth Muscle Cells. (From Barker, after Huber and 

 De Witt.) a, Axis cylinder; h, its termination; n, nucleus of muscle cell. 



TECHNIC 



(i) Fix spinal and sympathetic ganglia in formalin-Miiller's fluid (technic 6, 

 p. 7). Stain sections with ha^matoxylin-eosin (technic i, p. 20), or with hiema- 

 toxylin-picro-acid-fuchsin (technic 3, p. 21). 



(2) Fix spinal and sympathetic gangUa in absolute alcohol or in lo-per-cent. 

 formaUn, and stain sections by Nissl's method (technic, p. 39). 



(3) See also technic i, p. 452. 



(4) Ganglia should also be prepared by Cajal's silver method, using the al- 

 cohol fixation (p. 38). 



EFFERENT PERIPHERAL CEREBRO -SPINAL NEURONES 



It has been seen that the bodies of these neurones lie in the ventral 

 part of the neural tube where they form a part of the ventral gray 

 column in the cord and the "motor" nuclei of cranial nerves in the 

 segmental brain. The axones of these cell bodies emerge as the 

 efferent roots and usually either pass -{via the white ramus coms 

 municans, in spinal nerves) to various sympathetic gangUa to ter- 

 minate there, or proceed as the efferent fibres of the peripheral nerve- 

 to terminate in the striated voluntary muscles of the body and head. 

 In the spinal nerves these fibres pass beyond the spinal ganglia and 

 then join the afferent fibres; in some cranial nerves they pass out 

 with the afferent fibres. On their way to the muscles the motor axones 

 may bifurcate several times, thus allowing one neurone to innervate 



