140 Proceedings of the Eoyal Society of Edinburgh. [Sess. 
XV. — The Harmala Alkaloids in Malaria. By J. A. Gunn, M.D., 
D.Sc., Professor of Pharmacology in the University of Oxford ; and 
Lt.-Col. D. G. Marshall, M.B., Lecturer on Tropical Medicine in the 
University of Edinburgh. 
(MS. received June 21, 1920. Read June 21, 1920.) 
A. — HARMALINE IN TRYPANOSOMIASIS AND MALARIA. 
(J. A. Gunn.) 
1. Introductory. 
In two former contributions to this Society I described the pharmacological 
actions of harmaline * and harmine,f the two alkaloids found in the seeds 
of Peganum harmala. In regard to harmaline I came to the following 
conclusions “ It differs from most alkaloids in that it does not exert, to 
the same extent as they do, a selective action on one kind of tissue. It 
attacks not only highly specialised tissues such as voluntary muscle, muscle 
of the heart, blood-vessels and uterus, and cells of the central nervous 
system, but also less highly differentiated cells, such as pigment cells, 
protozoa ( Raab ), and ciliated epithelium (Jacobson). 
“ In this account of its pharmacology the actions of harmaline have been 
shown to resemble very closely those of another alkaloid, of which the 
above type of non-selective action is also true, namely, quinine. As a 
pharmacological agent, harmaline ought to be grouped with quinine, and 
therefore with those substances which are conveniently, if somewhat 
indefinitely, termed protoplasmic poisons. 
“ Considering the close resemblance in the pharmacological actions of 
harmaline and quinine, one is led to anticipate some corresponding similarity 
in their therapeutic effects. With this subject I hope to deal on a 
future occasion.” 
In regard to harmine, it was found that “ the pharmacological actions 
of harmine resemble very closely those of harmaline, in so far as the 
symptoms produced in the intact animal and the effects produced on the 
various systems and tissues are qualitatively the same in the case of both 
alkaloids. Harmine is, however, only about half as toxic as harmaline.” 
Upon this pharmacological basis I have since then endeavoured to 
obtain evidence as to the value of these alkaloids in protozoal diseases, 
* Gunn, Trans. Roy. Soc. Edin., xlvii, 1909, pp. 245-272. 
t Gunn, ibid., xlviii, 1911, pp. 83-96. 
