640 Third European Journey 



Dr. Gye is today the director of the Imperial Cancer Research 

 Fund. In a recent lecture, " The Propagation of Mouse Tumours 

 by means of Dried Tissue," ^^^ given before the Royal College of 

 Surgeons on March 22, 1949, he has described three sarcomas 

 propagated in mice with the use of a complicated technical pro- 

 cedure. His conclusion is still that experimental evidence points 

 to cancer having a " continuing cause, and that this, in mammals 

 as in birds, is a virus. ... At present the only conclusion from the 

 whole work which is of vital and abiding interest," Dr. Gye says, 



is that it is no longer justifiable to put the normally easily filterable tumours 

 of chickens in a separate class and turn a rather scornful eye on them. 

 This work has now brought tumours of mice — average tumours found in 

 all well-equipped cancer laboratories — into the same class. They have, as 

 was to be expected, a continuing cause, and, since the continuing cause of 

 chicken sarcoma is a virus, probably it is viral in nature. 



In his letter to Dr. Smith of November 1926 he had said: 



The technique of filtration is of course one of the most obscure and 

 difficult jobs in filterable virus work. . . . We are using collodion filters 

 which can be graded with some approach to precision. And the results 

 are now being standardised /'/ it is possible against the "" depositing power " 

 of centrifugalisation. For the purposes of centrifugalisation we have now 

 a better machine — a real engineering job — which will spin 15,000 rev[olu- 

 tion]s a min[ute], record the speed and enable us to repeat with accuracy 

 any given experiment. 



His address of more than two decades later evaluates much of 

 the modern knowledge of Dr. Rous's chicken sarcoma. " The 

 agent," he said, 



which multiplies with the growth of the tumour is now recognized as a 

 virus. Electron-microscope photographs have been taken, and the sizes 

 revealed by such photographs are in fair harmony with sizes deduced from 

 experiments with collodion filters. The virus is more or less spherical and 

 occurs in clumps in the tumour cells. Now we know of several hundred 

 filterable tumours of the domestic hen. They are of different structures: 

 some, but very few, are simple spindle-cell tumours resembling the Rous 

 sarcoma ; others include chondromas, osteochondromas, fibrosarcomas, 

 myxosarcomas, muscle-cell tumours, and so on. . . . [I}t has universally 

 been found that the inoculated virus can start a tumour only of the kind 

 from which it is derived. . . . Tlie virus is so specialized in its effects that 

 it represents in itself all the qualities and properties of the cell from which 

 it is derived. Nevertheless, an immune serum made by injecting virus 



(With colleagues), British Med. Jour., 511-515, Mar. 26, 1949. 



