PREFACE 



"But not by nature is the man of science more critical 

 or careful than his colleagues are. What gives him an 

 advantage over them is that when issues rise in his 

 domain they can be settled with a sureness and 

 dispatch which elsewhere are unknown; for science 

 has a priceless touchstone here to seek out truth — the 

 technique of measurement." 



Edmund W. Sinnott in Science and the Education of 

 Free Men, American Scientist 32: 209 (1944). 



Like a lens gathering diverse rays and concentrating them in a 

 new beam which penetrates depths hitherto unilluminated, each 

 new border science reveals a new threshold of knowledge. We who 

 work in the life sciences stand at such a threshold today. The lights 

 of histology and cytology are being joined with those of chemistry, 

 and the brilliant new beams converging to a focus probe beyond 

 the old limitations. The day is past when our vision cannot penetrate 

 beyond the architecture of the cell. The wealth of knowledge that 

 has been, and can still be gleaned from purely descriptive microscopic 

 anatomy is not to be minimized, but under the new illuminations 

 we can begin to discern the chemical patterns in the cellular archi- 

 tecture. From this knowledge an understanding of the functions of 

 the patterns will follow. Thus, from histology and cytology, as we 

 have known them in the past, the new field of histo- and cyto- 



XI 



