other details, shows that semen was drawn four times (two ejaculations each time) from Pen-state Inka Paul in April; a total of 51.5 c.c. of semen, which was diluted to 976 c.c. and used for 473 inseminations. If natural mating had been practiced, Penstate Inka Paul would have served eight cows that month.

Chart C gives Penstate Inka Paul's Individual Sire Efficiency Record for a part of 1946. The cumulative figures show that 31 drawings were made from him January through July; the semen, properly diluted, was used for 3,062 inseminations, of which 2,071 were first services; 710, second services; 213, third; and 68, fourth to cows hard to get in calf. In January and February of 1946, as shown in the right-hand column, 67 percent of cows that received Penstate Inka Paul's semen became pregnant after one insemination. This rate of conception compares very well with natural mating. Charts like C are kept for each bull on the basis of receipts issued by the 10 inseminators and submitted once a month to headquarters.

Altogether, about 40,407 cows have been inseminated in 21 months.

A committee for each breed recommends the purchase of a bull, after close scrutiny of its pedigree and past performance.

The cooperative's balance sheet on June 30, 1946, showed total assets of 354,186.71, including buildings and improvements, $15,438.10; office equipment, $404.86; laboratory equipment, 5563.06; barn equipment, 516,431.14; and bulls owned, 56,410. Revenues for the month were 55,316.15, including $5,176 in service fees. Expenses for the month totalled $2,004.83 (leaving an operating margin of $3,311.32). The major expenses were bull lease ($101.75); feed and hay (S321.66); salaries for 4 men ($783-35); shipping the semen (S80.32); and depreciation expenses ($321.55).

The cooperative has 21 directors, chosen by local units on basis of one director for each 1,000 cows or major fraction. They meet bimonthly. The technicians meet at least twice a year to consider suggestions for improving their work, discuss plans and projects, and to talk things over with workers at Pennsylvania State College, among them Joe S. Taylor and R. H. Olmstead, extension dairy specialists, John O. Almquist and C. B. Knodt, of the dairy research staff, and others. The directors and the manager also attend State conferences of artificial-breeding cooperatives.

Caution in every detail of handling the animals has meant that there never has been a serious accident at the headquarters. A strong stanchion is used to tie each bull every morning until operations are complete. All bulls are curried every day before releasing. Doors between inside and outside pens are controlled by an overhead rope and operate on an inclined track. The doors can be opened and closed without entering the bull's pen. When the receipts are received at the central office from the local technicians, they are tabulated according to date of service, bull used, and whether first, second, third, or fourth service under the heading "services". An asterisk denotes the date semen was drawn from each bull, and the figures above it indicate the motility at time of drawing (70 percent in the case of Inka Paul) and (32 days) the length of time that semen showed life in the refrigerator. As any of these services are repeated, the receipt carries the information as to date of original service, and the bull that failed to get the cow pregnant. The failures are tabulated opposite, under the heading of "Returns," and the number of returns are counted at the end of 30 days, 60 days, and 180 days, and transposed to the monthly record of the Individual Sire Efficiency Record as of Penstate Inka Paul.

Chart B (page 4), shows how information on all bulls of all breeds is collected from the records of individual bulls and individual breeds. It shows, for instance, that in January 65 samples of semen were obtained from the bulls at Tunkhannock and were used for 2,688 inseminations; probably 1,750 cows were gotten in calf (although a few cows required as many as five services), and the average number of inseminations per cow was 1.53.

Chart C is part of the record that tabulates the efficiency of the 10 local groups for January 1946. It shows, for example, that 426 cows belonging to members of Tunkhannock Local No. 1 were bred that month; of that number, 76 were rebred within 30 days; 133 were rebred in 60 days, and 141 rebred by the end of 180 days. As shown in the right-hand column, 67 percent of the cows bred never returned for service. The information for this record is collected from receipts of the corresponding month.

Chart D is the technician's monthly record of work at one local unit, the one in Wayne County, Pa. It gives data on inseminations and payments by members. Information is added as it becomes available from the locals' monthly records.

Above, Schaefer and Horrocks are shown wrapping test tubes of semen for shipment to the technicians. Each technician is sent a predetermined portion of the diluted semen (based upon his estimated needs) from the particular bulls from which semen had been collected that day —enough to inseminate 15 to 30 cows, although, of course, the technician may not have that many calls from dairymen members that day. The semen is first diluted with egg yolk-citrate, then cooled in a refrigerator in the laboratory, put in tubes, packed with cans of ice, wrapped securely, and sent on its way, by automobile, special delivery mail, and sometimes by airplane. Most of the members live within 100 miles of Tunkhannock; some live as far as 150 miles away.

Artificial breeding has developed into one of the greatest advances in the field of dairy husbandry. It is making available the use of sires of proved ability to dairymen who otherwise would have to depend upon bulls of a much poorer quality. It should improve our dairy cattle at a rate which could never be accomplished with natural breeding. Some bulls have now been used in the artificial breeding of more than 10,000 cows each, and there is every reason to believe that in the near future many times this number will be bred to a single bull during his lifetime. It now appears that if proper care is exercised, artificial breeding will be valuable in preventing the spread of certain types of diseases.