Syjnptomatology. Semeiology. 27 



In eruptions on the skin (erythema, eczema, pustule, squama) 

 a cause may be found in the local action of heat, friction, or other 

 direct irritant, but in the absence of any such manifest cause, an 

 enquiry should bs made into the functions of sanguification, 

 digestion, urination and the action of the liver. It may further 

 suggest parasitism (ring worm, phthiriasis, fleas, acariasis, ver- 

 minous disease, etc. ) 



Symptoms of nervous disorder are too numerous tO be here 

 traced to local lesions. Motor paralysis of one limb may, how- 

 ever, suggest injury to its motor nerves, to the same side of the 

 spinal cord, or of the oppo.site half of the cerebrum. Paraplegia 

 almost always indicates injury to the cord. Senory paralysis of 

 one .side may depend on disease of the opposite corpus striatum. 

 The animal moves in a circle when a tumor (coenurus in sheep) 

 exists in the roof of the lateral ventricle presumably pressing on 

 the ganglia on its floor. An animal rolls on its axis when there 

 is a lesion of the median cerebral peduncles, of the supero-ex- 

 ternal portion of these peduncles, of the posterior part of the ence- 

 plialon, or of different parts of the hemisphere. Amaurosis sug- 

 gests disease of the corpora quadrigeminia. I^oss of coordina- 

 tion of muscular movement usually implies some lesion of the 

 cerebellum. Vertigo may imply disease of the encephalon (con- 

 gestion, anaemia, inflammation, dropsy, haemorrhage, tumor, 

 abscess) ; it may be disease of the internal ear ; it may be diges- 

 tive disorder connected often with cryptogamic poisoning ; it may 

 be heart disease with obstruction of the jugular veins ; it may be 

 parasites in the nasal sinuses ; or it may be disease of the eye. 

 Coma occurs in most congestions and pressures on the encephalon, 

 and like vertigo in poi.soning by alcohol, solanine, monoxide of 

 carbon, etc. In acting on any ganglionic centre the agent may, 

 according to its degree, operate positively or negatively, produc- 

 ing spasms, or paralysis as the case may be. As in the case of 

 other visceral affections the specific diseases must be referred to for 

 particular symptoms. 



For the more precise points in diagnosis, including chemical, 

 phy.sical, electrical and instrumental methods, etc., the reader is 

 referred to the special diseases. 



