38 THE ROYAL SOCIETY OF CANADA 
probable explanation of the sefacts is that many of these adventive 
organisms cannot grow in the udder, or else they are destroyed by the 
action of the leucoevtes which are present in large numbers in all milk. 
Since the flora of the foremilk varies, since it usually contains 
organisms not found in the rest of the milk, and may not contain those 
of the strippings at all, since the cocci characteristic of the strippings 
are neither motile nor exceptionally rapid growing, and further, in view 
of the results obtained from ‘‘Lady Edith” by sealing over the teats,— 
the authors conclude that it is probable, that only the lower part of 
the udder in a milking animal undergoes external invasion. 
Regarding the balance of the milk, the possibility of the source of 
contamination being an internal one becomes more probable, when 
seriously considered, than it did to earlier writers, who either neglected 
it altogether, or merely gave it passing attention. This phase of the 
question, however, is of such a nature as to render direct proof practi- 
cally impossible. All attempts at colonizing the udder with such germs 
as B. fluorescens, B. prodigiosus and others have failed. By smearing 
the teats with cultures we could not induce M. varians to colonize in 
“Nessie” or “Lady Edith,” though the organism was evident in the 
foremilk after each application and sometimes remained for several 
milkings. The instance given by Ward of a germ which caused an ob- 
jectionable odour in milk being located in the udders of a certain herd 
seems the only recorded case of anything like an invasion taking place. 
On the other hand, Ford has shown that saprophytic bacteria 
may occur throughout the organs of normal small animals. The same 
fact was demonstrated by one of us in connection with cattle, and we 
also found similar organisms in ’’virgin” udders. Several analyses 
made from the organs of some horses that were killed during the progress 
of some experiments on the swamp fever of horses revealed the presence 
of from 1 to 6 species of bacteria, among which yellow and white cocci 
were much in evidence. M. acidi lactici and M. varians were identified, 
and, while others were not specifically determined, there is every reason 
for believing them to be closely related to these forms. From these 
results we conclude that the flora of the latter part of the milk comes, 
as a rule, from an internal source. 
Regarding the time of entrance, these experiments would show 
that before the animal freshens the udder is not subject to external in- 
vasion, that is, to any noticeable extent. However, it is clear that 
virgin udders do contain such bacteria as may be found occurring 
throughout the internal organs of the animal. Nothing was done to 
ascertain whether these apparently harmless saprophytes are con- 
genital or not. 
