p 
I.— PHYSIOLOGY. 223 
] 
lethal action of the alkaloid on the pneumococci, appear to be concerned. 
_ Evidence was obtained by Moore, for example, which suggested that the 
defensive reaction of the host was an essential factor in the cure, optochin, 
in doses inadequate to kill the pneumococci, rendering them liable to 
the action of specific antibodies; and some experiments of Felton and 
Dougherty suggest that an excessive dose of an alkaloid of this class, by 
suppressing the natural defensive reaction, may even allow the fatal 
spread of an infection which a lower dose would cure. Morgenroth, on the 
other hand, emphasises the part played by the organotropic properties of 
optochin and vuzin, in enabling the red corpuscles to act as carriers of the 
drug to the point of action, and the connective tissues to form local 
_ depots of it. 
An acridine dye, named Trypaflavin, was under study in Ehrlich’s 
laboratory in 1914 as a trypanocidal remedy, and was found during the 
war, by Browning and his co-workers, to have valuable properties as an 
antiseptic for infected wounds and mucous membranes, for which, under 
the name ‘ Acriflavine,’ it is still used. Since the war, other dyes of this 
series have been investigated by Morgenroth and his school, and one of 
them, called ‘ Rivanol.’ is stated to be particularly effective as a tissue anti- 
septic, especially in conditions of spreading infection due to streptococci. 
NH, 
C2H,0 
NH, 
N 
*Rivanol’ (2-ethoxy 6, 9 diamino acridine). 
} In the case of ‘ Rivanol’ also, evidence has been brought forward that 
it is fixed by the red corpuscles and the subcutaneous tissues, protected 
thereby from excretion, or held at the point where its curative action is 
required. From these body cells it is suggested that the dye is gradually 
given up to the cocci, on which its action is exerted, by a process 
called ‘transgression’ by Morgenroth. This is a process by which a sub- 
stance is passed from one medium to another, when both have strong 
affinities for it, through a layer of an intervening medium for which it has 
‘no affinity, and in which it may be almost insoluble. In this process of 
depot formation, and gradual liberation of the active substance, we are 
concerned with a phenomenon which certainly has a widespread impor- 
tance for chemotherapeutic action. We have earlier seen evidence of such 
fixation and gradual release in the cases of Bayer ‘ 205 ’ and Salvarsan. 
Another suggestive feature of the action of ‘Rivanol’ on streptococcal 
infections, is that such organisms as escape the immediately lethal effect 
of the dye appear to have lost their hemolytic properties, and to have 
en modified into a relatively avirulant strain. 
