Future of Infectious and Malignant Diseases 
correlated with the presence of antibodies against different 
viruses in a given segment of the population is an undertaking 
of much more heroic measure and the results of such a venture 
may not justify its undertaking. 
Outline (for the future) of possible therapeutic approaches 
The success of possible future therapeutic approaches will be 
related to the way in which the character of the tumour cell was 
acquired, and whether the tumour cell is of the autonomous or 
of the dependent type. 
Therapeutic approaches can be divided into attempts by 
physical, chemical and biological means. 
The physical approach is based essentially on surgical removal 
of the tumour or destruction of the tumour by other means. 
Early diagnosis and skilful surgery have been in the forefront 
of the therapeutic approaches to the problem of malignancy. 
Since it is expected that surgical techniques in the future will 
improve at an even more alarming rate than at present, every 
primary tumour growth will be accessible to total extirpation. 
The problems which remain will relate to the multicentric 
origin of the primary tumour and to metastases (secondary 
development). Simultaneous development of cancer cell foci 
in the two lungs makes the surgical approach futile. Recur- 
rences and metastases present an even more perplexing prob- 
lem, although it is quite certain that the majority of malignant 
cells in the circulating blood do not form metastases. ‘Two 
factors which are at present under consideration are the changed 
state of the endothelium lining the blood vessels which permits 
effective passage of a metastatic cell and the possiblity that the 
arrested metastatic cells are genetically altered in comparison 
with the majority of the tumour cells and can therefore pene- 
trate more effectively into the endothelium and resist the largely 
unfavourable situation of the organism vis-d-vis cancer cells. 
Outright surgical procedures can also be applied to autono- 
mous types of cancer which acquired their characteristics from 
without or from within, but in dependent types of tumours 
which acquired their character from without they do not make 
209 
