TACTILE SENSE. 



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nerves. These are in direct anatomical relation with the central 

 nervous system. By means of these nerves the cortical portion of the 

 cerebrum, endowed with consciousness, perceives the impressions com- 

 ing from the external world. These are the so-called special, external 

 and objective sensations. 



Among the parts furnished with nerves of general sensibility are 

 the mucous membrane of the digestive, respiratory, and genito-urinary 

 tracts, and the skeletal muscles. In the digestive tract, the mouth, 

 pharynx, and anus are endowed with tactile nerves; the rest of the 

 tract is furnished with nerves of general sensibility. The mucous 

 membrane of the oesophagus gives us the sensation of thirst, the 

 gastric mucous membrane the sensation of hunger and satiety, while 

 the rectal membrane notifies the individual of the need of defecation. 



Pulmonary tissue in itself has but very little sensibility; but ab- 

 normal irritations cause cough and painful sensation. The pleura, 

 when invaded by disease, produces very painful sensations. 



The genito-urinary membrane, besides its exquisite tactile sensi- 

 bility, is also the seat of general sensibility that is doubly modified: 

 in the need of urination and the sexual sense. The kidneys, ureters, 

 testes, Fallopian tubes, and the uterus are endowed only with nerves 

 of general sensibility. 



The skeletal muscles are furnished with the so-called muscular 

 sense. 



Muscular Sense. According to Dr. Sherrington, of Liverpool, 

 this is a specific sensation obtained from specific sense-organs in 

 muscles, tendons, joints, and all the accessory organs of movement. 

 In the muscles of the skeleton there are three sets of sensory organs : 

 muscle-spindles, tendon-organs, and Pacini corpuscles. 



Muscle-spindles, or neuromuscular spindles, are long, narrow 

 bodies, with a thick sheath of connective tissue enclosing fine striped 

 muscular fibers. Sensory, medullated nerve-fibers enter the spindle, 

 dividing into branches, and losing their medulla form endings around 

 and between the muscular fibers. The perception of muscular sense 

 may be grouped into: (1) those of posture; (2) those of passive 

 movement; (3) those of active movement; and (4) those of resist- 

 ance to movement. 



To the organs of muscular sense is largely traceable a local 

 feeling of fatigue. 



The nerves of muscle are competent to produce pain; this is 

 proved by the pain of muscular cramp. 



A proof of muscular sense is the employment of enough force 





