FATS AND THEIR ECONOMICAL USE IN THE HOME. 5 
very slightly assimilated by the body when eaten alone, whereas, 
if mixed with palmitin and olein digestibility is increased because, no 
doubt, the mixture has a lower melting point than the stearin by 
itself. 
The digestive disturbances often attributed to eating fat are prob- 
ably due not so much to the inability of the body to digest the fat 
itself as to other factors, chief among which are bad cooking, 
overeating of foods containing fats, and rancidity. Laboratory ex- 
periments have shown that under some conditions, when fats are 
overheated, a chemical compound called acrolein is formed. This 
substance is especially irritating to the mucous membranes of the 
eyes, nose, and throat, and it is well known to housekeepers that when 
fats are scorched vapors are given off which cause the eyes to water. 
If any of these vapors were occluded in the food during frying it 
seems probable that similar irritation would be produced on the deli- 
cate mucous membrane of the digestive tract. Obviously, such di- 
gestive disturbances can not be cited as proofs of an incomplete 
digestion of fats. 
Disagreeable sensations are experienced by some people after 
eating large quantities of foods such as meats containing much fat 
interspersed with the muscular tissue, and overrich puddings or 
salads. This may be explained by the fact that the digestive juices 
of the stomach have little solvent action on such nonemulsifled fats 
and are thus hindered from digesting the protein which is covered 
by or very intimately mixed with the fat. The passing of the food 
through the pylorus into the small intestine is thus delayed until 
the fat has become separated from the lean portions by the enzymic 
and mechanical action of the stomach. For this reason very fat 
meats, for instance, remain a longer time in the stomach than lean 
meats, although in the end they are as thoroughly digested. Similar 
digestive disturbances are sometimes experienced after eating fried 
foods (cooked without scorching) or foods in which fat is incorpo- 
rated in such a manner that it prevents the digestive juices from act- 
ing upon the protein and carbohydrates. This delayed digestion is 
often mistaken for diminished or incomplete digestion. Fats which 
have become rancid, even though the rancidity is not sufficiently 
marked to influence the flavor very much, may cause digestive dis- 
turbances in some people. That this is not always the case is evi- 
denced by the fact that there are some oriental people who eat rancid 
butter or oils apparently by preference. 
It must be remembered that there are some persons whose systems 
can tolerate little if any food rich in fats. This, like the inability of 
some to eat strawberries, onions, or other foods, without digestive 
disturbances, is a matter of individual peculiarity. 
