ABSTRACT
Removing a cell from its natural surroundings and anatomical relationships is to lose important aspects of its function. As important a tool as cell culture has become for the study of biological cells, it is not an all-purpose solution—far from it. Although studying cells embedded in that environment, in whole animals, that is, in situ, overcomes this problem, it poses major difficulties of its own. Though time honored and frequently an absolute necessity to gain real understanding, in situ research introduces all the unknown and unspecified complexities and confusions of the whole animal and at times makes interpretation challenging at best. The pieces of tissue were not only responsive, the response was large, roughly the same as seen when the tissue was fresh several hours earlier. Exocytosis might have gradually shut down not due to tissue death, but to the absence of a stimulant.
