B.— CHEMISTRY 



6i 



and O'Connor, 1917), showed them to be of little or no value in the 

 treatment of amoebic dysentery. 



The method of Dobell and Laidlaw, however, depending on the cultiva- 

 tion of amoebae in a medium consisting partly of solid (inspissated fresh 

 horse-serum) and partly of liquid (egg-white diluted with Ringer's fluid) 

 with a little starch, gave results which fell into line with the clinical results. 

 Emetine was found to be fifty times as toxic to amoebae in vitro as N- 

 methylemetine, woemetine, and 0-methylpsychotrine, which are clinically 

 inactive. The clinical inactivity of woemetine (Low, 19 18), a stereo- 

 isomeride of emetine, is interesting and reminiscent of the difference 

 between d- and /-stereoisomerides in the cases of adrenaline and hyos- 

 cyamine. Later, Laidlaw, Dobell and Bishop described a simpler 

 medium, consisting of i part of sterile horse-serum, 8 parts of Ringer's 

 fluid with a small quantity of sterile solid rice-starch, disodium hydrogen 

 phosphate being added as a buflFer. In this medium, they found that the 

 amoebae were destroyed in four days by emetine i in 5,000,000, provided 

 that the medium did not become too acid. We have made use of this 

 method in the work which I am about to describe. 



In 1927 Brindley and Pyman suggested a constitutional formula for 

 emetine, and in 1929 Child and Pyman synthesised a series of compounds 

 (II) having similar constitutional features in that they contained two 

 6 : y-dimethoxytetrahydrowoquinoline nuclei united through the 1:1' 

 positions by chains of methylene groups. 



CH2 CHg 



/\ /\ 

 MeCH CH CH, 



CH3O 



CH3O 



CH3O 



CH3O 



CH CH, 



CH 



N 



HN 



CH2 H2C 



CH, 



OCH, 



OCH, 



CH, 



(I) 



I (CHa)™ j 

 CH CH 



NH HN 



CH, 



CH2 H2 



OCH, 



OCH, 



CH, 



(11) 



When tested by Mr. Tate and Miss Vincent, working under Prof. 

 Keilin's direction, at the Molteno Institute at Cambridge, using the 



