71 



DISCOVERY 



it is a loss of sensitiveness to restraint, cannot be 

 said with certainty at present. AlthoiiBh some cancers 

 can be scin to increase in size from day to day, others 

 progress so slowly that it may take months to be 

 certain of any change, and tlie latter arc no less fatal. 

 The problem is subtle and alluring, and it is doubt- 

 ful if it can be yet stated in a form suitable for direct 

 attack. Until progress has been made, the causation 

 and origin of cancer can only be partially compre- 

 hended, for we simply do not know what it is that 

 arises, or is caused. 



Another possibility, which has e.xerted a consider- 

 able influence on the course of cancer research, is that 

 the cancerous change is due to the entrance of a 

 microbe, with peculiar properties, into the cells pre- 

 pared for its reception by chronic damage. Dr. 

 Peyton Rous, of New York, has discovered that 

 certain tumours of the domestic fowl can be trans- 

 mitted to other fowls without transferring the intact 

 tumour cells. These growths are indistinguishable, 

 in structure and in the course of the disease, from true 

 cancers. The agent responsible is almost certainly 

 a microbe, so small that it lies below the limit of 

 microscopic vision. These obser\-ations of Rous 

 have been hailed as indicating the direction in 

 which to look for the explanation of all cancers, but 

 even the most enthusiastic supporters of this point 

 of view will admit that it is still unproved, except 

 for three or four cancer-like growths of the domestic 

 fowl. Experiments to test this explanation on the 

 tumours of mice and rats and of man have failed 

 completely. 



One of the great disadvantages which retards pro- 

 gress in the study of cancer is the absence of a means 

 of producing the disease at will in experimental animals. 

 Although, as has been already mentioned, we can carry 

 over cancer cells from an animal in which it has arisen to 

 health^' animals, and produce in them all the symptoms 

 of the disease as it occurs naturally, it is not yet possible 

 to induce the cancerous transformation at will in the 

 cells of normal animals within a reasonable time. 

 Prolonged exposure of rats to X-rays has in a few in- 

 stances been followed by cancer, and experiments are 

 at the present time being carried out in different 

 countries with pitch and tar to try and produce the 

 form of cancer which follows chronic irritation with 

 these substances. It may be asked whether all in- 

 dividuals are equally liable to develop cancer under 

 chronic irritation. The differences which have been 

 observed in the parts of the body most frequently 

 attacked by cancer in the different animal species 

 and races of men, are sufficiently definite to make this 

 unlikely. Even such closely related animals as rats 

 and mice suffer from cancer in very different organs. 

 Breeding experiments with mice have been carried out 



on a large scale here and in .America, and have shown 

 that it is possible to obtain stocks which differ enor- 

 mously in their liability to develop cancer. The exces- 

 sive liability which some of these stocks show can be 

 transmitted to their offspring. It is therefore probable 

 that hereditary predisposition may play a part in human 

 cancer also, but, as is obvious, such intensive selective 

 mating as has been carried out in mice is unlikely to 

 occur accidentally in man. 



The conception presented in the preceding pages 

 is that cancer involves a local disturbance of the deli- 

 cately balanced mechanism which, running smoothly 

 in the healthy body, maintains its component cells 

 as a harmonious whole. Beyond stating that the 

 disturbances must have taken place and been per- 

 petuated in the cells, which by their continuous division 

 make up the cancerous growth, little is known. Those 

 engaged in the study of cancer are heartened in their 

 work by the conviction that, soon or late, the human 

 mind will penetrate and master the intricacy of these 

 balanced forces, and therewith bring the growth of 

 cancer under control. 



BOOKS SUGGESTED FOR FURTHER READING 

 Tumours, Innocent and Malignant. J. Bland-Sutton. 

 The Pathology of Tumours. E. H. Kettle. 

 The Experimental Study of Cancer : A Review. W. H. 



Woglom. 

 Lectures on the Pathology of Cancer. C. Powell White. 



The Stamp Act of 1765 



II. What George Grenville Did — 

 and What He Ought to Have 

 Done 

 By C. H. K. Marten, M.A. 



Assistant Master, Eton College 



In the last number of this Journal tlie conditions 

 and circumstances preceding the fatal Stamp Act were 

 discussed. The British Government, as the Colonies 

 seemed unwilling or unable, owing to their different 

 circumstances and jealousies, to combine for their own 

 effective defence, had decided that it was necessary 

 to keep a permanent force of 10,000 men in America 

 for defence against the Indians, a most dangerous 

 rising of whom had just been suppressed. But the 

 question arose who was to pay for this army ? The 

 head of the British Government at this time was 

 George Grenville. He belonged, perhaps, to the most 



