194 EQUINE PHYSIOLOGY. 



in some way with the sympathetic system, but their function is 

 not known. 



The Spleen probably influences digestion, and Shiff and Herzon 

 claim that the secretion of trypsin, one of the pancreatic ferments, 

 is dependent on it. 



In its structure are found pigment, broken-down red corpuscles 

 and many leucocytes. It also serves as a reservoir for the ab- 

 dominal circulation. It can be removed without loss of life, and 

 is a blood gland. 



The Thyroid and Thymus have to do with the elaboration of 

 blood, otherwise their function is unknown. 



The Pituitary Body and Conarium also properly belong in 

 this category, but their function is unknown. 



THE NERVOUS SYSTEM. 



The nervous system connects into a coordinated organism all 

 parts of the body. It receives all impressions, regulates all move- 

 ments, voluntary and involuntary, and the functions of secretion, 

 nutrition, calorification and all processes of animal life. (Flint.) 

 The cerebrospinal system consists of the brain, cord and the var- 

 ious nerves, and presides over animal life. The sympathetic pre- 

 sides over nutrition or organic life. 



(For structure of nerves, see Anatomy of Nervous System.) 



Termination of nerves. 



To voluntary muscular fibi-es the nerve divides and spreads out 

 into plaques. 



To involuntajy fibres^ it loses its tubular membrane and ter- 

 minates in the nucleus as the axis cylinder. 



The Sensory 7ierves terminate — 



((^) As minute plexuses with no fixed arrangement. 



{b) As the tactile co7puscles or end bulbs of Krause, found most 

 abundantly in the lip, hoof, sheath and glans penis. These are 

 small capsules of connective tissue, the nerve terminating in a 

 plexus or bulbous extremity. They have also a central termina- 

 tion either in the brain or cord, connected to a cell pole by an 

 axis cylinder. After its origin a nerve does not inosculate but 

 passes to its terminus. 



Nerves are divided into molar and sensory, the former ending 



