1884.] 
NATURAL SCIENCES OF PHILADELPHIA. 
281 
ON THE BEHAVIOR OF PETROLATUM IN THE DIGESTIVE TRACT. 
BY N. A. RANDOLPH, M. D. 
The mixture of hydrocarbons,, recognized by the pharmacist 
under the name of petrolatum, and popularly used under the 
commercial names of cosmoline or vaseline, presents on super- 
ficial inspection few points of difference from some of the organic 
fats of the same consistency. Close examination reveals differ- 
ences, both in physical properties and in chemical constitution, 
between the bodies just compared. One point of difference, which 
I have as yet been unable to find recorded, lies in the respective 
behavior of these two groups, when in contact with the absorbent 
surfaces of the digestive tract. Tims, while the organic fats, as 
ordinarily taken in food, are readily and almost completely ab- 
sorbed, this soft paraffin is entirely rejected, and found unchanged 
in the feces. 
During eight days, I took daily one-half ounce of commercial 
vaseline, in addition to my regular diet. Digestion was in no 
wise altered, and no appreciable results ensued. Later, two 
healthy adults each received, in the course of forty-eight hours, 
one ounce of vaseline. Their alvine dejections for three days from 
the beginning of this observation were collected and dried, and, 
at the suggestion of Dr. John Marshall, of the University of 
Pennsylvania, extracted with petroleum ether. Making a slight 
allowance for incompleteness in extraction, the vaseline ingested 
was, in each case, recovered in its totality, showing that it had 
passed through the econom}7 unchanged and unabsorbed. 
There are some important medical applications of these facts, 
tl'e discussion of which would be out of place here, and which I 
reserve for further experiment; but the following deductions ap- 
pear permissible, and are of strictly biological interest. 
I. Pure petrolatum, while entirely unirritating to the digestive 
tract, is valueless as a food-stuff. 
II. The results of the experiments here described lend support 
to the theory that oleaginous matters are dependent, for their 
absorption, not upon mechanical, but upon vital activities, and 
that in such absorption the selective power of the protoplasm of 
the intestinal epithelium is manifested.