382 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1946 
be ascertained by thumping. Auscultation, that is, listening to the 
chest, was practiced by Hippocrates and was aided by shaking the 
chest. This was done by placing the ear to the chest until Laénnec 
(1817) invented the first stethoscope. He gained his idea for the use 
of a hollow tube by observing children listening to the sound of taps 
on. hollow logs. 
The X-ray was discovered in 1895 and, like so many other discover- 
ies, had its beginning in an accident. It was by mere chance that 
Roentgen was working in the dark with a tube of glass containing 
various gasses at low pressures (the Crookes’ tube) and happened to 
notice that a small piece of paper covered with a coating of barium 
plantinocyanide shone brightly. Fortunately he had the foresight to 
suspect that this might be of importance and the persistence to investi- 
gate the possibilities until he obtained convincing evidence of the value 
of these strange rays. This discovery was one of the most dramatic 
events in the history of science. Asan example of how the imagina- 
tion of the world was stimulated by it, the bill may be cited which 
Assemblyman Reed, of New Jersey, introduced in the State legislature 
in 1896 to prohibit the use of X-ray opera glasses in theaters. 
In the nineteenth century knowledge of disease was sought mainly 
through studies of morbid anatomy; that is, by observing the effects 
which disease produced on the tissues. Gradually interest developed 
in the study of the ways in which the functions of the body are dis- 
turbed in disease—pathologic physiology and biochemistry. This 
approach bore fruit because with better understanding of disease pro- 
cesses methods were developed whereby disease may be recognized 
much earlier than it once could be. Furthermore, such knowledge has 
led to the discovery of methods of treatment which are directed at the 
primary cause or at least correct the abnormality which has been 
produced. 
Advances have been made in so many fields that it would be im- 
possible to discuss them all here. Many problems relating to man have 
been approached through experiments in animals, and it is safe to 
say that they would probably never have been solved otherwise. An 
example is found in the story of the conquest of diabetes. 
In 1920, Frederick Banting, a physician in London, Ontario, while 
preparing a lecture at the Western Ontario Medical School on the 
relation of the pancreas to diabetes, ran across the report of a rare 
case of stone in the pancreatic duct. The author of that report pointed 
out that blockage of the pancreatic duct by the stone had caused atrophy 
of all the pancreatic cells except certain small groups known as the 
“islets of Langerhans.” These were the cells which were known to be 
damaged in persons suffering from diabetes. In the case cited, dia- 
betes had not developed. 
