PARASITIC DISEASES OF CATTLE IN PUERTO RICO 15 
who wish to dose regularly, a concentrated stock solution may be 
made by dissolving 200 grams of copper sulphate in 1 Liter of 
distilled water or rain water. Such a solution will retain its 
strength indefinitely. In making the dilution for administration, 
add 50 cubic centimeters of the stock solution to 950 cubic centimeters 
of water, or in this proportion. 
Prevention, — Confined calves should be provided with dry sanitary 
pens and should be fed on uncontaminated grass. Pastured animals 
should be given a wide range on dry hillside pastures. If necessary, 
both the confined and pastured animals should be treated. Periodic 
treatments, every 2 or 3 w r eeks, should be given instead of waiting 
until the animals show symptoms of the disease. On some pastures 
where heavy stocking is practiced, it is necessary to dose every 2 
weeks during the wet season. 
Figuke 4.— Calf with "papera" or edematous swelling underneath the jaw. This calf 
was infested with stomach worms. 
THE NODULAR WORM 
The nodular worm (Oesophagostomum radlatum) is about 15 milli- 
meters (five-eighths of an inch) long. It has a characteristic solid 
white body. The adult worms live in the large intestine. The lar- 
val worms live in nodules in the wall of the intestines and occasion- 
ally make their way to the mesenteric lymph glands, the omentum, 
or the liver. The nodules are usually found in the terminal portions 
of the small intestine. 
Life history. — The eggs are passed with the manure and the young 
worms are hatched and undergo some development on the ground. 
When swallowed by cattle, the young worms enter the walls of the 
intestine and remain for a few days and then return to the lumen 
of the large intestine, where they reach maturity. Following this 
encysted stage in the walls of the intestine, the nodules formed 
often increase in size and contain a yellowish or greenish, cheesy or 
calcareous material. 
