Focal Symptoms. 593 



pie, in disease of the crura or the pons there is marked contrac- 

 tion of the pupils with absence of, or exaggerated reaction, to 

 light, and possibly also strabismus. Spasms of the muscles of 

 the neck are due to stimulation of the sensory nerves in the re- 

 gion of the medulla and generally result from meningitis. 

 Finally, now and then a local symptom may be attributed to a 

 reflex in cases in which a circumscribed portion of the body is 

 involved. 



Movement in circles is very rarely observed, but when this 

 does occur it is always in the same direction. This sjaiiptom 

 may accompany diseases of the portion of the central motor 

 tract extending from the cortex to the medulla oblongata, the 

 movement being either towards the diseased or the healthy side. 

 Movement in circles associated with lateral bending of the head 

 and neck is principally seen in diseases of the cerebellum or the 

 middle peduncle of the cerebellum, and it may also be observed 

 in association with unilateral blindness or deafness. 



In cases of unilateral lesions of the anterior and medial portions of the 

 thalamus produced artificially in cats and dogs Probst observed lateral bending 

 of the head and movement in cireks lasting for some minutes, in the first place 

 away from the injured side and then for several days towards that side. Destruc- 

 tion of the tissues included between the posterior portion of the thalamus, the red 

 nucleus and the anterior pair of the corpora quadrigemina caused bending of the 

 head and movement in circles towards the injured side. Destruction of tissue in 

 the region of the posterior pair of the corpora quadrigemina, the pons and the 

 pyramidal decussation caused movements in the opposite direction while lesions of 

 the posterior part of the pons caused rolling. 



Hyperextension of the head and neck is observed in disease 

 of the portion of the brain posterior to the cerebellum. 



Rolling movements associated with rotation of the head 

 about its long axis in the same direction are somewhat fre- 

 quently observed in small animals. The animal, as a rule, lies 

 on its side and then rolls over. The eyes are often involved, 

 that towards which the rolling takes place being turned in- 

 wards and downwards and the other upwards and outwards. 

 In many cases the former only is involved. In view of the fact 

 that the nuclei of the cranial nerves are situated near the pedun- 

 cles of the cerebellum there are often functional disturbances 

 of these nerves (ocular motor, trochlear, trigeminus abducens, 

 facialis) . 



Rolling movements are usually seen when the disease involves the 

 peduncles of the cerebellum or the surrounding tissues. Experiments 

 and observations have proved that such movements are not of neces- 

 sity associated with disease of the middle peduncle. They occur with 

 far greater frequency in cases of disease of the anterior part of the me- 

 dulla oblongata and the hemispheres of the cerebellum. Probst's ex- 

 periments have sho\m that unilateral lesions of the posterior part of 

 the thalamus may sometimes cause rolling movements, and IMontane 

 saw them in inflammation of the corpus striatum. The latter obser- 

 vation is, however, not absolutely conclusive as the possibility of the 

 presence of perhaps only microscopic lesions in the peduncles of the 



