648 



Chronic Dropsy of the Ventricles. 



to the time of death. The quantity of liquid in the ventricles 

 in cases of hydrocephalus may be from 40 to 120 grams (Her- 

 ing). Dexler was able in a single case only to show increased 

 pressure in the cranial cavity after death. 



According to Dexler there is in the first place dilatation of 

 the lateral ventricles and of the anterior part of the third ven- 

 tricle. As a result of this the brain, the weight of which is 

 found to be normal after the escape of the liquid, is enlarged, 

 and the liquid passes into the lymph spaces of the cranium and 

 especially into those of crura cerebri, the pituitary body, the 

 decussation of the optic nerves and the fossa of Sylvius. In 

 view of the fact that the brain is enclosed in a bony case the 

 dilatation of the lateral ventricles cannot be very great. The 



Fi'^. 88. Chronic hydrooepliaus internus. Section posterior to the hemispheres. 



a. Swellinij- formed by the medial portion of tlie occipital lobes (c) ; b. Posterior 



border of the flattened corpora cpiadrigemina; d. Aqueduct of Sylvius reduced in 



caliber to a lissuredike opening, e. Optic chiasma. 



dilatation is most pronounced in the middle portion of the ven- 

 tricle and in the vertical direction, and least in the inferior 

 horn, l)ecause in healthy horses there is often some adhesion 

 here and this prevents dilatation. The olfactory bulbs are 

 somethiies dilated to a certain extent. The septum pellucidum 

 between the two lateral ventricles is stretched and sometimes 

 perforated. The posterior part of the third ventricle appears 

 reduced in size owing to tlie bulging of the corpus mammilare 

 into tlie lumen. In consequence of this the aqueduct appears 

 to be either greatly reduced in caliber or even completely closed. 

 On the other hand, the anterior third of the ventricle appears 

 to be l)roader, the recessus infundibuli occluded owing to the 



