188 | ANNUAL REPORT SMITHSONIAN INSTITUTION, 1946 
in 2 quarts of warm water, with the addition of some medium such as 
acacia solution to maintain suspension during the procedure. After 
fluoroscopic and roentgenographic examinations the patient evacuates 
the suspension. 
Conditions diagnosable by X-ray include varicose veins in the 
gullet, ulcers, and tumors in the stomach or duodenum. Before 
the days of X-ray, duodenal ulcer was considered a rarity; a person 
with severe and prolonged indigestion was usually diagnosed stomach 
ulcer. Since the development of Roentgen methods it has been found 
that most such cases are actually due to duodenal ulcer, the latter 
being over 20 times as common as gastric ulcer. This was one of 
numerous revolutionary findings during the first two decades of this 
century. 
Gastric cancer is one of the most common and serious malignant 
tumors in man; unfortunately it tends to be asymptomatic in its early 
stages and therefore its presence is not manifested until it is pretty 
well advanced. Persistent disturbance of digestion in men over 40 
renders X-ray examination of the stomach advisable. The growth 
shows as a small intrusion on the barium shadow or as a small zone 
of immobility of the stomach wall. 
The normal appendix usually is visible at some time during X-ray 
examination of the intestinal tract. It may be seen to fill and empty 
but if it does remain filled for some days this finding alone is not of 
grave importance. The X-ray evidence of acute disease in the ap- 
pendix consists of marked local tenderness, absence of or incomplete 
filling, delay in the passage of the barium in the adjacent terminal 
inches of small bowel, and, occasionally, a local inflammatory mass. 
However, the diagnosis of acute appendicitis is more reliable when 
made by methods other than radiological ones. 
X-ray examination is invaluable in the study and elucidation of the 
various diseases of the colon. 
The liver and spleen are normally visible in most abdominal 
roentgenograms. Their visibility may be enhanced by intravenous 
injection of thorium dioxide sol (thorotrast), a drug which has the 
property of depositing itself in the small cells lining certain portions 
of the liver and spleen (the reticuloendothelial cells). The thorium 
is opaque and aids in the diagnosis of certain tumorous and cystic 
diseases of these organs. After 7 years, thorium degenerates into a 
mildly radioactive product, but the amount necessary for ordinary 
examination has been shown to be so small that no harmful late radio- 
active changes develop. Another area of the alimentary tract which 
may be examined by selective methods is the gall bladder. If you 
ingest a suitable iodine preparation, the material will be excreted in 
your bile and will be concentrated in the gall bladder; provided the 
