PHAKMACOLOGY OF HYPOPHYSEAL EXTRACTS 755 



normal potassium chlorid and two and a half parts of tenth normal sodium 

 chlorid as a standard; and the comparative contraction of the melano- 

 phores as the index of the strength of posterior lobe extracts. The method 

 has not yet been tested sufficiently to allow any conclusion as to its general 

 availability. 



Pharmacodynamic Effects of Posterior Lobe Extracts. Extracts of 

 the posterior lobe of the hypophysis usually stimulate smooth muscle to 

 contraction. Magnus and Schafer (1901-02) first observed that a diminu- 



Fig. 5. The constrictor and the relaxing effect on the isolated loop of the in- 

 testine of a posterior lobe preparation. (After Shamoff, Am. J. Physiol.) 



tion of splenic volume occurred after their injection, this was confirmed 

 by Dale (6) (1909) ; and Frankl-Hochwart and Frohlich (1910) reported 

 that the bladder was similarly affected. Although Dale and Laidlaw 

 (1912-13) failed to obtain such an effect Hoffman (1912) confirmed the 

 earlier observations in demonstrating that the reaction occurred after 

 intraspinal injections of the extract thus demonstrating its absorption 

 from the canal and indirectly supporting Cow(a) (1914-15) in the idea 

 that the normal path of the hypophyseal secretion to the organism is by this 

 route. Nevertheless, since Carlson and Martin (1911) and Jacobson 



