FREDERICK S. HAMMETT 



by Hamilton and Rowe (1916) as better than the isolated uterus test be- 

 cause frequently the uteri used are variable in their response. Heidelberg 

 and Pittenger (1914) and Pittenger (1917) consider that the blood- 

 pressure method is inherently faulty not only on the basis of Herring's 

 (1914) idea of a greater uterine sensitivity to potent extracts, but also 

 on the basis of the presence of both pressor and depressor substances in 

 such extracts, the algebraic sum of the effect of which is recorded by the 



Fig. 4. Graph showing concordant results obtained from the application of re- 

 peated doses of an equal amount of pituitary extract to the isolated uterus of the 

 virgin guinea-pig. (After Pittenger, Biochemic Drug Assay Methods.) 



pressor method while no indication is given of the oxytocic value. This 

 argument is supported by the observations of Adams (1917) already re- 

 ported. As far as the irregularity of response of the uteri is concerned it 

 would appear from the study of Hatai and Hammett (1920) as if the 

 factors of heat, age and previous emotional conditions of the test animals 

 are among the causes of variability, arid that these disturbing factors can 

 be eliminated by a proper choice of animal for the test. 



Spaeth ( a) (fr) (1918) raises objections to both the isolated uterus 

 method and the pressor method on the basis of a hyper- and hyposensitivity 

 respectively. He reports experiments in which he used the melanophores 

 of Fundulus heteroclitus as the test-object ; a mixture of one part of tenth 



