Histological Appearances of the Mammalian Pituitary Body 157 



in the pituitary of the cat epithelial cells may even grow into its central 

 cavity. 



A substance histologically resembling the colloid of the thyroid gland, 

 but probably of a different nature, occurs in large quantities in the nervous 

 portion of the posterior lobe. It appears to be a product of the epithelial 

 cells, and, in the cat at any rate, to be carried by lymphatics into the 

 central cavity, and so into the third ventricle of the brain. In this respect 

 the posterior lobe of the pituitary is an infundibular gland. Whether this 

 substance is modified by its passage through the nervous substance or not 

 is unsettled. Its distribution corresponds with the site of the tissue, the 

 extracts of which have active physiological results when injected into the 

 blood. 



The anterior lobe of the pituitary is extremely vascular and its circula- 

 tion sinusoidal. The posterior lobe is supplied for the most part by a 

 central artery which enters it at its postero-superior angle and runs forward 

 giving off branches; the veins begin immediately below the epithelial 

 investment and run backwards in this situation, to emerge near the entry 

 of the artery. The veins of both lobes enter large blood sinuses lying close 

 to the sides of the pituitary body. 



Histological evidence is against the statement of Be la Hall er that the 

 anterior lobe is a tubular gland which pours its secretion directly into the 

 subdural space. 



I am indebted to Mr Richard Muir for the care with which he has 

 executed the drawings and photographs accompanying this paper. 



The expenses of the research have been defrayed by a grant from the 

 Moray Fund for the prosecution of research in the University of Edinburgh. 



LITERATURE REFERRED TO IN THE TEXT. 



(1) Benda, "Beitnige zur nornialen und pathologisclien Histologie der menscli- 

 lichen Hypophysis cerebri," Berlin, klin. Wochenschr., Bd. xxxvii., S. 1205, 1900. 



(2) Berkley, "The Finer Anatomy of the Infundilmlar Region of the Cerebrum, 

 including the Pituitary Gland," Brain, vol. xvii., p. 515, 1894, 



(3) BoEKE, "Die Bedeutung des Infundibulums in der Entwickelung der 

 Knochenfische," Anat. Anz., Bd. xx., S. 17-20, 1902. 



(4) BuKDACH, Vom Baue und Leben des Gehirns, Bd. ii., S. 108-9, and 

 Bd. iii., S. 469, Leipzig, 1819-26. 



(5) Glaus and Van der Stkiciit, " Contribution a IV'tiide anatomique et 

 clinique de I'acromegalie," Annale-s et Bulletin de la Sue. dc Mt'd. de Inuid, p. 71, 

 1893. Quoted from Benda (1). 



(6) Cyon, " Beitriige zur Physiologic der Schilddrvise und des Herzens," 

 Pfluger's Archiv, Bd. Ixx., S. 213-16, 1898. 



