24 CARL G. HARTMAN 
in his statement concerning the mammary glands. For, during 
the 1916 season, I found that by simple palpation of the mam- 
mary glands within the pouch I was able to diagnose with a 
high degree of accuracy the state of the imternal reproductive 
organs, so responsive are the glands to the physiological changes 
going on in the animal just before and after oestrus. By this 
method one is enabled to select from the animals on hand those 
that are likely to furnish eggs or embryos. Thus out of the 
hundred animals Nos. 300 to 400, used at the height of the 
breeding in 1917, only a half-dozen failures are recorded. A 
typical case of misjudgment is that of No. 326, in which ‘5-mm. 
vesicles’ were predicted and ripe follicles found in the ovary; 
or No. 354 in which ‘bilaminar blastocysts’ were expected and 
the animal was found in pro-oestrus. Sometimes a later stage 
than the one predicted will be found, as is, of course, to be 
expected from individual variations that are general in all 
. physiological processes. The method has resulted in the saving 
of a great deal of time, effort, and material, especially during 
the last breeding season. 
Unfortunately, however, the physiological changes which the 
mammary and other reproductive organs undergo are identical 
immediately after oestrus whether pregnancy ensues or not. 
This holds true for the mammary glands more than for the other 
organs, and it is impossible during the first five or six days to 
distinguish externally between pseudopregnancy and pregnancy. 
As ovulation is always spontaneous, the internal organs behave 
the same in both conditions. The vaginal loops begin to retro- 
gress even before ovulation. The uteri are almost maximum in 
size when the minute eggs first reach them; in pregnancy they 
remain bright red and turgid and possess a peculiar luster like 
polished red agate; but, if the eggs are unfertilized, the uteri, 
after four or five days, become dull and dark red and then 
flaccid and collapsed. The corpora lutea are somewhat more 
persistent in true pregnancy. But the mammary glands con- 
tinue development even after the degeneration of the corpora. 
and the involution of the uteri are well under way. 
