HILARY KOPROWSKI 
hoped that a systematic study will lead to discovery of a variety 
of stimulants which would make the non-specific type of therapy 
or prophylaxis a specific one. 
Since macrophages and possibly other cells of the lymphoid 
tissues obtained from mice and birds bearing chemical or virus- 
induced tumours were found specifically to destroy tumour 
cells, immunological recognition of specific tumour antigens by 
cells of the tumour-bearing host may take place more frequently 
than is suspected, but in most cases the fast-multiplying tumour 
cells overwhelm the defences of the host. If future generations 
find means to stimulate these recognition mechanisms and, ¢0 
ipso, slow the development of the tumour, the future prevention 
or cure of malignant diseases should not look so bleak. 
Finally, continuing our daydreaming, if means are found to 
induce changes in the process of cell differentiation which favour 
the rise of cells capable of taking care of many common and 
uncommon infections, the “‘ milieu intérieur’’? of man in the future 
may have a totally different aspect to the “‘ milieu” of the present 
victims of pathogenic sabotage. 
So far as a “‘ milieu extérieur’’ is concerned, an environmental 
factor which plays an almost universal role in making man more 
susceptible to infection is subclinical protein malnutrition based 
on unbalanced composition of amino acids in the diet. As soon 
as this deficiency is corrected, the increased susceptibility to 
infection disappears. Other environmental factors such as 
habits, stress, climate, and protection against infection at a 
young age are also known to play a réle in changing the 
susceptibility of man to infections. Alas, there is no indication 
as yet of how to change the human environment in such a way 
as to bring about the greatest resistance to the pathogenic 
challenges encountered during man’s lifetime. Perhaps this 
task will be more successfully tackled by future generations. 
LETTER TO MY GREAT GRANDSON IF HE INTENDS TO 
BECOME A HEALER 
“It is funny, you will be dead someday.” 
e. e. cummings: sonnets—actualities II 
214 
