ACTIVE PRINCIPLES OF PARS NEURALIS 



of the many investigators are capable of performing even a 

 crude biological assay; or (c) enormous variations in the con- 

 centration of the oxytocic hormone occur. 



The author believes that most of the results can be ex- 

 plained by the first of the three conclusions just mentioned. 

 Van Dyke, Bailey, and Bucy (1929) found that ventricular 

 or lumbar cerebrospinal fluid had no effect on the isolated 

 guinea-pig uterus provided that the ionic composition of the 

 "physiological" fluid in which the uterus was suspended be- 

 fore assay was exactly the same as that of the cerebrospinal 

 fluid. If the only variation introduced was an increase in the 

 calcium-ion concentration, a uterine contraction resembling 

 that produced by a posterior-lobe extract followed. There- 

 fore, it appeared probable that ionic differences between the 

 cerebrospinal fluid tested and the "physiological" solution in 

 which the uterus was first immersed could account for many 

 of the positive results of other authors. All adequately con- 

 trolled experiments in which the detection of the oxytocic 

 principle in cerebrospinal fluid has been attempted have 

 failed (Whitehead and Huddleston, 1931; Friedman and 

 Friedman, 1933; and Simon, 1933).^ 



Experiments in which the oxytocic effect of blood, blood 

 serum, or extracts of these has been demonstrated likewise 

 appear to have little significance. ** 



* Samples of cerebrospinal fluid of man and animals under various experimental 

 conditions have caused the contraction of the isolated uterus. In none of the follow- 

 ing reports, however, is there satisfactory evidence that the oxytocic effect was 

 due to the oxytocic principle of the pars neuralis: Cow (191 5); Dixon (1923); 

 Dixon and Marshall (1924); Trendelenburg (1924); Janossy and Horvath (1925); 

 Miura (1925); Blau and Hancher (1926 — most of their experiments were negative); 

 Dixon and Wadia (1926); Mestrezat and van Caulaert (1926-27); van Dyke and 

 Kraft (1927); Geesink and Koster (1928-29); Hoff and Wermer (1928); McLean 

 (i 928) ; Sato ( 1 928) ; Trendelenburg (i 928) ; Trendelenburg and Sato ( 1 928) ; Janossy 

 and Magoss (1930); Karplus and Peczenik (1930-33); Barbour and Hambourger 

 (1933); and Colombi and Porta (1934). 



9 McLean (1928); Pontes (1929-31); Da Cunha (1931); Figueroa (1933); Bell 

 and Morris (1934 — in preparing extracts, these authors added HCl to plasma and 

 brought the mixture to boiling; after these steps the concentration of HCl was still 

 3.6 per cent); Donnet (1934); and Caroca and Koref (1935). 



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