272 



Herrinir 



pressure may show a temporary slight fall or remain unaltered. The 

 frequency and force of the heart-beat are unaffected. 



The kidney frequently shows a slight expansion, but not a continued 

 one. The secretion of urine is unaltered or very slightly increased. The 

 difficulty of isolating completely the proper tissue of the anterior lobe from 

 the elements of the posterior make it probable that any effect obtained b}^ 

 the injection of its extracts is brought about by the inclusion of a little of 

 the posterior lobe. If the dissection be so made as to avoid the junction 

 of the two lobes, extracts of the chromophil portion have practically no 

 action. It seems, therefore, that the anterior lobe or chromophil segment 

 aorees in the inactivity of its extracts as well as in its structure with the 

 anterior lobes of the pituitary of mammals and birds. 



Posterior Lobe. 



The general effect of extracts of the posterior lobe is similar to that 

 brought about by extracts of the mammalian and avine posterior lobes. 



Fig. 5. — Effect of injection into the jugular of a cat of 5 c.c. of an extract of the posterior lobe- 

 pars intermedia and pars nervosa — of the cod's {lituitarj-. (12 glands in 40 c.c. Ringer.) 

 The arrow on the kidney oncograph indicates an artificial lowering of the writing point. Notice the rise 

 of blood-pressure and rapid expansion of liidney, as well as the well-marked diuresis. 



The blood-pressure is almost immediately affected. A considerable rise may 

 take place, preceded sometimes by a slight fall, or the increase of blood- 

 pressure may be only trivial. The same extract frequently produces 

 different results when injected into different cats. In one animal the rise 

 of blood-pressure may be marked, in another very slight, and that notwith- 

 standing that no previous injections of any kind have been made in these 

 animals. Howell pointed out that a repeated dose of pituitary extract 

 does not produce the same results on blood-pressure as are brought about 

 by the ffrst injection, and this observation holds true of extracts of the 

 posterior lobe of the pituitary of avine and teleostean pituitaries as well. 

 The immunity conferred by a first dose does not last very long, and varies 

 with the amount and strength of the injection given ; but, in order to obtain 



