STIMULATION OF REPRODUCTIVE ORGANS OF CATTLE        307

specific cause for sterility. All took the bull for the first time for many months.
Three have since proved in calf, three remain under treatment, and two have been
discarded.

The injection certainly gives encouraging results in cases slow to breed again
after calving. Of 7 cows injected 5 came into oestrum within 3 weeks, to ok the
bull and have proved in calf. Two took the bull but did not hold, and are still
under treatment. Two buffalo cows injected have also come to the bull and held.

                                                Technique.

In the cases quoted in this note we have used raw urine filtered through a
Chamberland L 3 filter, using an exhaust pump. In some cases the dose was very
small, and latterly we have adopted the dosage recommended by the Institute of
Animal Genetics, and are now using a modification of their technique for the
preparation of urine.

The urine is collected from a known pregnant cow. The later in pregnancy the
better. It may be collected in a clean mug as it is passed, or drawn off by
catheter. This is not essential and most cows strongly object to catheterisation.

About 400 c.c. are required for each case. The dose being 10 c.c. per 100 lb.
body weight, injected on four consecutive days.

The urine is placed in a flask and to each 100 c.c. is added 5 c.c. of a 20 per
cent. solution of sulpho-salicylic acid and well shaken for ten minutes to precipitate
proteins. It is allowed to stand and settle or may be passed through a coarse
filter paper. The clear liquid is then acid and must be neutralised by the addition of
bicarbonate of soda. We continue adding bicarbonate and stirring until it is faintly
alkaline to litmus. It should then be poured into sterile bottles, capped and sealed
with parafin wax. One dose in each bottle.

If it is to be kept for some time it would be better to pass it through a
Chamberland filter L 3, and to run a thin layer of toluol over the surface to prevent
oxidation. If it is then kept in cold storage it is believed it will remain potent for
several months.

Hormone, which is probably a mixture with a predominance of the secretion
of the anterior pituitary gland, is not specific and may be used for other animals.
It is also active in bulls. We have not tried it in other males.

                                            Hormone in bulls.

We have used this injection in one old bull, off service from old age, 3 full-
grown bulls, off service, and four young ones to bring them on to service. One