16 
E. ZSCHOKKE. 
tococcus of infectious mammitis exerts a harmful action upon 
the cells of the milk glands. Even if these structures do not 
die as a result of its action, they at least lose their physiological 
function and cease to yield milk. Afterwards, when the harm¬ 
ful influence is not at work, the secreting cells generally resume 
their function only when incited by the natural cause (par¬ 
turition). 
This appears to be a general law. A healthy cow when 
dried off can only exceptionally be brought back to lactation 
before calving again. There are, however, exceptions. iVmong 
them is one reported to us by District Veterinarian Hohn, of 
Richtersweil. A cow which, on account of mammitis, had not 
been milked for many weeks, later, before she had calved, again 
yielded a considerable mess of normal milk. We here have 
made a similar observation in a case treated by us. 
Among goats, which, as is well known, go dry very early 
while non-pregnant, the spontaneous return of the milk secre¬ 
tion is occasionally observed in the spring in non-pregnant 
animals. 
Reviewing the economic disasters which follow almost regu- 
'larly the treatment of an udder whose secretion is wholly 
purulent and without regular milk constituents, the question as 
to whether or not any treatment is worth while must be earn¬ 
estly discussed. We have already pointed out (Landw> Johrbuch^ 
1893, and Schweiz. Archiv. fur Tierheilkunde , 1897) that the 
type of infectious mammitis, which is associated with short strep¬ 
tococci, which latter the white blood corpuscles are able to take 
up and destroy, recovers without aid by means of the curative 
power of the corpuscles, provided that the udder is not milked 
out for five or ten weeks. 
On the other hand, that type which is recognized by the 
presence of very long streptococci persists for a long time after 
the animal has been dry, because the corpuscles are unable to 
take up and destroy the streptococci. 
These observations have been confirmed by later experience. 
When cows suffer from the curable type of infectious mammitis 
