The salivary secretions in health and disease.

The potential usefulness of analysis of the salivary secretions in diagnosis and 
prognosis is beginning to be explored in depth. The preliminary work 
already undertaken indicates that modern methods applied to this secretion may 
provide information that is different from that obtained in other body 
fluids. Saliva is collected at the point of its manufacture and, 
therefore, is unaffected by collection or storage in the body. It 
is the product both of protein synthesis within the glands and 
of most of the known water and electrolyte exchange mechanisms. Salivary 
composition is affected by both autonomic and hormonal stimuli. As the 
specific influence of each of these factors is better understood, studies 
of this fluid will provide important clues to the understanding of 
disease and the evaluation of therapy. There are few places in 
the body where it is possible directly, utilizing a non-invasive technique, 
to examine the product of a large number of important biological 
processes. It is obvious that careful handling of collection and analytic 
techniques are essential if these secretions are to be utilized. Future 
investigations in clinical situations should take full advantage of the strong 
base of knowledge of the physiology of these glands. Development of 
this field depends on careful clinical investigations designed to make full 
use of our current knowledge. 