486 IOWA DEPARTMENT OF AGRICULTURE 
adjacent glands greatly swollen. The autopsy revealed generalized tuber- 
culosis, involving the lungs, mediastinal glands, spleen, liver and kidneys. 
Tubercle bacilli of the bovine type obtained from the mesenteric glands 
of a sheep, hog, and cow were similarly transformed in their morpholog- 
ical appearance after being passed through a series of cats and recovered 
on dog serum. These bacilli also increased in virulence, as the last cat 
in the series invariably succumbed in a shorter time than the first of the 
series.- 
These experiments and observations indicate that the types of tubercle 
bacilli are very inconstant, and that under suitable conditions they readily 
change both in morphology and in virulence. A similar conclusion was 
reached by other investigators in working with the avian and piscine 
types of tubercle bacilli several years ago, and was reasonably to* have 
been expected with the human and bovine type. 
It must be plain to all, from these recent developments, that too much 
has been made of the slight differences in cultural characteristics, in 
morphology, and in virulence which have been observed in some cases 
in comparing the human and the bovine bacilli. The observations were 
interesting, and it was important that they should be followed up until 
their significance was made entirely clear; but it was almost unpardon- 
able error, from a sanitary point of view, to promulgate sv/eeping gener- 
alizations calculated to arrest and abolish important measures for prevent- 
ing human tuberculosis before the soundness of these generalizations had 
been established by a thorough course of experimentation. 
When Koch said in the British Congress on Tuberculosis that he should 
estimate the extent of infection by the milk and flesh of tubercular cattle 
and the butter made of their milk as hardly greater than that of here- 
ditary transmission, and that he therefore did not deem it advisable to 
take any measures against it, he went far beyond vvhat was justified by 
any experiments or observations w'hich he reported, and he did an im- 
mense amount of harm, which -will be manifested for years to come to 
those who endeavor to guard the human race from the dangers of animal 
tuberculosis. The researches which have been alluded to make these 
dangers more definite and certain than they have appeared before, and 
sanitarians should therefore most earnestly endeavor to counteract the 
erroneous and harmful impression which was made by Koch's address at 
London and his subsequent address at the International Conference on 
Tuberculosis at Berlin. 
DISEASES OP YOUNG CALVES. 
SUSPENDED BBEATHIXG. 
The moment the circulation through the naval string is stopped the 
blood of the calf begins to get overcharged with carbon dioxid (CO2), and 
unless breathing is speedily established death promptly follows. For- 
tuneately the desire to breathe, roused by the circulation of the venous 
blood and the reflex action from the wet and chilling skin, usually at 
once starts the contractions of the diaphragm and life is insured. Among 
the obstacles to breathing may be named suffocation before or during 
