174 



Herring 



their arrangement, as shown by Cajal's method, is very complex. In the 

 adult cat the individual fibres are much thicker, and the cells fewer in 

 proportion to the size of the lobe. Neither by Cajal's nor Golgi's method 

 have I been able to find true nerve fibres entering the posterior lobe of the 

 cat's pituitary through the neck. The ependyraa fibres take on a lighter 

 stain by Cajal's method than the nerve fibres in the brain. Fibres can be 

 seen in the fully developed pituitary which are thinner and stain more 



Fig. 6. — Mesial sagittal section through developing pituitary body of a human foetus 

 (fifth month). Drawing from a photograph. 



a, optic chiasnia ; b, tongue-like process of epithelium ; c, third ventricle : rf, anterior lobe ; e, neck of 

 posterior lobe ; /, epithelium surrounding neck ; g, epithelial cleft ; h, posterior lobe. 



deeply. Some of them enter the epithelium round the neck of the posterior 

 lobe and ramify there. They are probably true nerve fibres which have 

 entered with the blood-vessels, and, as Berkley (5) states, derived from 

 the sympathetic. 



In the embryos of man, ox, and pig the posterior lobe is solid from an 

 early stage, and is relatively smaller than the anterior lobe. There is the 

 same close connection between the epithelium and the nervous tissue. In 

 fig. 6 a mesial sagittal section through the pituitary body of a human 



