GENERAL LYMPHANGITIS. 
215 
glacl to have the opportunity to lay my opinion before a meet¬ 
ing of veterinary surgeons for their critical perusal. 
Causes .—The causes are mysterious and can hardly be de¬ 
fined. Up to five or six years ago, this affection was little 
known, and has perhaps never been noticed before. Long 
continued rains and a subsequent inundation of the lower 
lands in all the valleys, caused the atmosphere to be moist, 
the nights chilly with heavy fogs that seldom cleared away 
before noon. Then it was that five or six months after that 
flood, this disease made its appearance amongst the mules of 
Roberts Island, near Stockton, and all along the tules and 
rivers, but soon the affection spread over the whole San 
Joaquin valley, up to the foothills, so that hardly any ranch 
in the valley was spared. Other localities of the State suf¬ 
fered from the same danger, and from that time until to-dav 
this mule affection appears and disappears in the different 
counties, and seems to be permanently located in our State. 
Work, care or feed cannot be accused of having any influence 
in the development of this disease, as animals have been ob¬ 
served to be attacked while in pasture or at rest in the stable 
and adjoining corrals, receiving at the time a very substantial 
nourishment. 
The question of contagion might be considered as causa¬ 
tive, but must be rejected as doubtful, until evident proofs 
are brought forward based on direct inoculation. My own 
experience is rather a proof against the contagious character 
of the affection, as I will relate it later. In the majority of 
cases, the disease was in all certainty of a spontaneous origin, 
and could not be traced to any particular cause by the owner. 
It seems rather to be due to a special climatic influence, that 
had the same effect in distant lying localities of the State at 
the same time. 
Physiological works tell us that the secreting organs or 
glands are far less active in mules than in horses, and daily 
experience teaches us that in general mules will perspire and 
urinate less than their equine companions in the same team. 
A similar fact has been noticed concerning the salivarv and 
intestinal glands. This circumstance explains why mules re- 
