BULLETIN 1281, U. S. DEPARTMENT OF AGRICULTURE 
muslin are securely fastened. From B the duct is 7 inches in diam- 
eter practically all the way down to the end. A second ring, 7 
inches in diameter, made of a somewhat lighter clock spring, is placed 
about 25 inches below B at B. Attached to this latter ring are 
several small rings to which stays may be fastened. As indicated 
in the sketch, from A to C is a slit so that A C B forms a flap of the 
muslin. The two side flaps are held together over the back by short 
leather straps by which the openings may also be regulated to con- 
form to the shape of the animal. From A to E and down to the ring 
B the duct is enlarged to such shape and size that the tail, which is 
kept within the duct, can be raised during the voiding of the excreta. 
The side flaps A C B start on B about 6 inches apart and by means 
of these the ring and duct are held against the body at a place where 
they do not interfere with the defecation or movements oi the animal 
and which permit the urine and feces to be conducted without loss. 
Fig. 1 — Duct in position on cow. 
This duct will remain in place on the animal without using straps 
between the legs. The duct received a coating of linseed oil to make 
it waterproof. This waterproofing failed to satisfy the requirements, 
and in subsequent experiments a loose lining of thin waterproof 
" stork sheeting" was used. With this modification the duct has 
been very satisfactory. 
PLAN OF THE EXPERIMENTS 
The general plan for the experiments with cows was the same as 
that followed in the experiments with steers, namely, to feed a given 
ration for a definite length of time, not less than three weeks, this 
time being divided into a preliminary feeding period and the so- 
called digestion period, usually of nine days' duration, during which 
the visible excreta as well as the milk were collected for analysis. 
The animals were watered daily as soon as they had eaten the morn- 
