40 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ I, I

known to be absorbed to a large extent. Most of the thymol administered and
practically all of the carbon tetrachloride in a therapeutic dose are absorbed,
although both are relatively insoluble, and carbon tetrachloride is more insoluble
in water than is thymol.

      In general, anthelmintics are rather selective in their action. One may remove
ascarids, but not hookworms or tapeworms ; another may remove tapeworms but
not nematodes ; another may remove hookworms but not ascarids. This fact
probably follows in part from the habits, physiology, and structure of the worms.
Some anthelmintics have a more restricted range of action than others, but we
have as yet no one dependable anthelmintic for all sorts of worms. Such worms
as whipworms, situated in the cæcum, and probably rarely subjected to the in-
jurious effects of substances taken by mouth, appear to be highly susceptible to
numerous anthelmintics if the drugs come in contact with the worms, and the
difficulty here appears to be to find anthelmintics which for one reason or another
will get to the cæcum in amounts sufficient to kill these worms.

      The form in which an anthelmintic is administered will often affect the result.
Thus, fluid extracts may contain active anthelmintics, but the alcohol present may
lead to rapid absorption of the anthelmintic in the stomach and upper intestine
with the production of systemic effects and the lessening of the anthelmintic effect.

      IV. Procedures in Anthelmintic Medication. The procedure in anthelmintic
medication may be as important as the selection of the drug. Thus, santonin
develops its action against ascarids much more effectively when it is given in small
doses repeated daily for a period of time than when it is given in one large dose.
Whipworms require the administration of bulky doses of a suitable drug, part of
which is likely to enter the cæcum, or else the repeated administration of small
doses of a suitable, non-irritant drug over a period of time in order to increase the
likelihood that some part of these doses will enter the cæcum. Preliminary
purgation, preferably with salts, appears to be important in treatments for the
removal of tapeworms, presumably because it is necessary to clear the mucus
away from the head of the worm if complete removal is to be obtained. The
use of the doudenal tube has been recommended for the administration of anthel-
mintics for the removal of tapeworms in order to avoid gastric absorption of the
drug, a point which deserves further study.

      Fasting is a matter of importance. It is not true, as was at one time
supposed, that fasting starves the worms and leads them to ingest an anthelmin-
tic carried in a tempting vehicle, such as milk, as we know that ascarids may
be kept alive for 26 days in such an innutritious medium as Kronecker's solution.
However, tasting is important in preventing the dilution of the drug in food