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 abdom- 

 inal 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 

 movements, voluntary and involuntary, and the functions of secre- 

 tion, nutrition, calorification and all processes of animal life. 

 (Flint.) The cerebro-spinal system consists of the brain, cord and 

 the various nerves, and presides over animal life. The sympa- 

 thetic presides over nutrition or organic life. 



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



Termination of nerves. 



To voluntary muscular fibres the nerve divides and spreads out 

 into plaques. 



To involuntary fibres, it loses its tubular membrane and ter- 

 minates in the nucleus as the axis cylinder. 



The Sensory nerves terminate 



(a) As minute plexuses with no fixed arrangement. 



(b) As the tactile corpuscles 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 termination 

 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 motor and sensory, the former ending 



