30 



INTERNAL SECRETION 



consists of the platinum chlorides of potassium and ammonium. 

 The octahedra are the ammonium salt. Since the prisms have 

 a percentage of 32' 8 i.e., 1'2 per cent, higher than would 

 correspond to the platinum salt of choline and since the free 

 base has a physiological action slightly different from that of 

 choline, it would follow that the base is not choline, but a 

 choline-like body, perhaps a di-choline anhydride. 



Fio. 8. Dog. A.C.E., morphine, curare, artificial respiration. Upper curve = 

 limb volume ; middle curve = intestine ; lower curve = carotid blood- 

 pressure. Effect of injection of 5 c.c. alcoholic extract of rabbit's brain 

 (Vincent and Sheen). 



Apart from this choline-like body, we did not find any choline 

 as such in brain extracts, and we fully confirmed the view of 

 Osborne and Vincent, and Vincent and Sheen, that the de- 

 pressor effects of nervous-tissue extracts are not due to choline. 

 We stated that the chemical and physiological tests recom- 

 mended for tin- -u I stance in pathological blood cannot be 

 n -lied upon : indeed, normal blood gives both the octahedral 

 crystals and the depressor effect on the blood-pressure, 



