600 VETERINARY PHYSIOLOGY 



the hypophysis, and consisting of cells with colloid material 

 between them. 



3. Physiology- — («) Removal of the true pituitary is generally 

 rapidly fatal; muscular tremors, slow pulse and respiration, and 

 a fall of temperature preceding death. Partial removal in 

 young animals is followed by decreased growth, persistence of 

 the infantile characters, and arrested growth of the gonads. 

 Often there is an accumulation of fat. The thyreoid is generally 

 hypertrophied. 



(6) Acromegaly, a disease in man characterised by greatly 

 increased growth of the bones, and more especially of the 

 intra-membranous bones, and with increased growth of the 



Cran turn 



Fig. 230. — Longitudinal section through the Hypophysis and 

 Pituitary. (Edinger. ) 



subcutaneous fibrous tissue, has been associated with disease of 

 the pituitary. According to Gushing, it shows two phases : — 

 First, the irritative phase, in which there is an increased growth 

 of bone and a premature development of the testis, and, second, 

 the destructive stage, in which the testes atrophy and the sexual 

 functions are in abeyance. Very probably the development of 

 giantism is associated with increased activity of the pituitary, 

 for, in most cases, an enlargement of the sella turcica has been 

 described. 



The fatal effects of removal may apparently be delayed for 

 a time by the transplantation of a part of the gland, but the 

 grafts do not persist. Administration of extracts of the 

 pituitary has not given conclusive results. It has ' been 

 claimed that a substance of definite composition which has 

 been called tethelin may be prepared from it, which first 

 decreases then increases the growth of young mice and causes 

 a persistence of the soft coat of the young animal. 



