4o8 SECTIONAL TRANSACTIONS.— B. 



I : 2-benzanthracene (Bachmann), which gives multiple tumours much 

 more rapidly than any other compound tested. 



Apart from 9 : lo-dimethyl-i : 2-benzanthracene two of the most active 

 cancer-producing compounds are 3 : 4-benzpyrene, a constituent of coal 

 tar which is undoubtedly responsible for skin cancer among tar workers, 

 and methylcholanthrene, which may be prepared in the laboratory from 

 cholesterol and the bile acids. Both these hydrocarbons are benzanthracene 

 derivatives with substituents at positions 9 (in the case of 3 : 4-benzpyrene) 

 and 5, 6 and 10 (in the case of methylcholanthrene). 



3 : 4-Benzphenanthrene has weak cancer-producing activity ; its 2- 

 methyl derivative is fairly potent, as is also 1:2:3: 4-dibenzphenanthrene. 

 The influence of substituents in other positions is being investigated (Hewett). 



Carcinogenic chemical compounds other than polycyclic hydrocarbons 

 are also known. 



Dr. T. Reichstein. — Partial synthesis of compounds related to the 

 adrenal cortical hormones (11.35). 



The suprarenal glands are essential to life and the total removal of these 

 organs leads to death. Each gland consists of two separate parts, the 

 medulla and the cortex, the latter part of the organ being associated with the 

 life-maintaining function. During the years 1929-1930 it was shown that 

 extracts of adrenal tissue could be prepared which on injection into adrenal- 

 ectomised animals maintained life. It seemed therefore that the most 

 important function of the adrenal cortex was the production of one or more 

 hormones. Such extracts are now prepared in large quantities for clinical 

 use. 



In several laboratories attempts have been made to isolate the ' cortical 

 hormone ' in pure form, and as a result of this work more than fifteen 

 different chemically pure substances have been separated all of which appear 

 to be sterol derivatives. Of these compounds only the four following sub- 

 stances possess biological activity in adrenalectomised animals. 



OH 



^ CO-CH2OH V ^' ^CO-CH,OH 



o^\/ 



I Corticosterone II Dehydro-corticosterone 



OH OH OH 



O /\ 

 -CO-CH2OH Y CO-CH2OH 



o^\/\X o^\/ 



III 17-Hydroxy-corticosterone IV 17-Hydroxy-dehydro- 



corticosterone 



Compounds I and II are more active than III and IV. These investiga- 

 tions are made difficult owing to the approximate nature of the biological 

 tests and the very large quantities of material they require. Furthermore 



