FUNGI IN COW ; S MILK. 757 
oe passed without notice. Out of a herd of about twenty- 
cows only one or two were attacked at first, and after giving 
tainted milk for a week or more they recovered, while one, 
two, or three more had in the meanwhile been taken ill. 
At first the whole of the milk was injured by the admixture 
of the impure, and it was only by setting aside a little milk 
from each cow in a separate vessel that the owner was 
enabled to fix on the affected ones. 
This unsusceptibility of the majority of the cows to the 
agent which all alike were swallowing, and the acquirement 
of this susceptibility by one after another at irregular in¬ 
tervals, demand investigation. One or two hypotheses may 
be hazarded on this subject. 
1st. It may be held that the agent operated on the system 
after the manner of a specific fever-poison, of which an 
animal is not always receptive, but which, received into the 
body, will follow a regular course of increase and decline, 
and obtain for the subject an entire immunity from all future 
attacks of the same kind. This theory fails to account for 
the introduction of the solid germs through the healthy 
mucous membrane of the stomach. The duration of the 
disease, too, does not show that constancy which this expla¬ 
nation would demand. There was a considerable variation 
in the different cases which occurred at Ithaca. In a case 
reported by M. Verrier, Seine-Inferieure, France, occurring 
like this in a dry season, and in which the milk had the 
same viscid characters, being easily drawn out into threads, 
and in all probability contained a similar cryptogamic pro¬ 
duct, the affection lasted in the whole herd for four or five weeks. 
2nd. Another theory, which I am more inclined to favour, 
would attribute the introduction of the spores into the cir¬ 
culation to some unusual or unhealthy state of the mucous 
membrane, whilst their elimination by the mammary glands, 
and probably by other secreting surfaces, was rendered 
possible by the fever and disturbance of the nutritive and 
secretory functions induced by their presence. The migra¬ 
tion of blood-globules through the walls of the vessels into 
the interstices of surrounding tissues during congestion and 
inflammation, affords some clue to a satisfactory explanation. 
A cow which is suffering from a slight indigestion has the 
mucous membrane congested and the normal relations be¬ 
tween its molecular elements impaired and deranged, and these 
minute bodies find a readier means of access to the blood. 
The same explanation may apply to the presence of many 
other allied elements in the blood of animals in diseases, 
such as the Bacteria, common to many fatal disorders in 
