710 E. V. COWDKY 



sphenoid bone, recent investigations have shown that its position is marked, 

 in quite a fcirge proportion of adult skulls, by a bony canal, the canalis 

 craniopharyngeus, and a case is on record in which the hypophysis occu- 

 pied this canal instead of the sella turcica. 



Structures from the Pharyngeal Portion of Raihke's Pouch (Hypophr 

 ysis Pharyngei). The pharyngeal portion does not atrophy, but gives 

 rise to a structure called the pharyngeal hypophysis, which is situated 

 in the middle line near the junction of the nasal septum and the roof of 

 the pharynx, as is illustrated in Fig. 1. Lewis states that a the size of 

 the pharyngeal hypophysis varies with age. It enlarges until middle life, 

 when it becomes stationary and remains of the same size. In the embryo 

 it measures three millimeters in length, in the newborn four millimeters, 

 and in the adult five millimeters. In width it varies from one half to one 

 millimeter. The pharyngeal hypophysis may have the form of a cord, 

 which, especially in the embryo and newborn, may be irregular, being 

 constricted at different points. It may have the shape of the letter S. 

 There is no capsule in the embryo and newborn, but in the adult the 

 connective tissue surrounding it is thicker and condensed to what might 

 be called a capsule. The alveoli which are found in children are small 

 and round or oval in form. Some of these in adults contain colloid. 

 The tissue presents all the histologic features of the anterior lobe of 

 the hypophysis occupying the sella turcica. The pharyngeal hypophysis is 

 to be regarded as an actively functioning gland, rather than a rudimentary 

 or involuting one." 



Pende(?;), on the other hand, is of the opinion that the tissue of the 

 pharyngeal hypophysis is less highly differentiated than that of the 

 hypophysis cerebri, and that it does not react in the same way experi- 

 mentally. Further information regarding the pharyngeal hypophysis may 

 1)0 obtained from Bryant's paper. 



Lobus Posterior. The posterior lobe of the hypophysis is formed as 

 a differentiation of the infundibular process of the hypothalamus and 

 presents few developmental anomalies. 



Growth and Development of Various Parts. The growth phenomena 

 of the hypophysis are interesting and suggestive, but unfortunately no 

 statistics are available for man. In white rats Hatai finds that a sex 

 difference appears in animals weighing fifty grains or more; that is to 

 say, at precisely the same stage of development as in the case of the 

 suprarenals. Jackson lias found, likewise in the white rat, that after 

 birth the anterior lobe increases and the posterior lobe decreases relatively 

 in size. Tlio relatively larger hypophysis in females he considers due 

 to the larger anterior lobe. "In young rats, held at maintenance of con- 

 stant body weight, the pars anterior is somewhat reduced, the intermedia 

 and nervosa being correspondingly larger" (Jackson). The pars inter- 

 media and posterior lobe resemble, therefore, the suprarenals and the 



