The Bulletin 
13 
It is a common belief in some sections of the State that cattle ex¬ 
posed at night in “milksick areas” contract the disease. This has sug¬ 
gested conveyance of the infection through the bites of arthropods or 
certain insects. 
A considerable number of writers who have studied the disease more 
recently than the ones just reported accept the theory of a parasitic 
origin of the disease. Among them are Maurel (1884), Boggs (1907), 
McCoy (1907), Crawford (1908), Jordan and Harris (1908, 1909), 
and Luckhardt (1909). The three last named authors alone have re¬ 
ported studies upon a definite microscopic organism. Jordan and Harris 
(1908, 1909), in their two extensive accounts, record the finding of an 
undescribed spore-forming bacterium, which they designate as Bacillus 
lactimorbi, in the liver, bile, and spleen of a heifer, in the liver of her 
fetal calf, in the pericardial fluid and gut nodule of a horse, in the 
brain, heart blood, and liver of lambs, in the feces of nonfatal cases in 
man, in the milk of cows, in the soil of milksick regions and in regions 
where milksickness has never been known, in normal cow dung, and 
on various grain and forage plants. They succeeded in several in¬ 
stances in isolating B. lactimorbi in pure culture from the heart blood 
and from certain internal organs of animals examined a few hours after 
death. They used in their experimental work rabbits, guinea pigs, 
dogs, cats, lambs, and calves. It may be briefly stated with reference to 
this work, that no well marked cases resulting in death were developed, 
although certain symptoms and lesions similar to those in animals nat¬ 
urally affected with milksickness were produced. In concluding their 
report, they assert that “taken as a whole, the facts do not indicate that 
a specific microorganism is the cause of milksickness or trembles. The 
bacillus in question belongs to a group which seems widely distributed 
and for the most part certainly not endowed with pathogenic qualities.” 
Luckhardt (1909) made further studies in the laboratories of Drs. 
Jordan and Harris on the physiology of Bacillus lactimorbi, on its 
distribution, and on its pathogenicity. He isolated the organism from 
alfalfa from farms in Wisconsin, Illinois, and Indiana, which supplied 
certified milk to Chicago and Milwaukee, and from four species of 
weeds, Bigelovia Rusbyi, Solanum eheagnifolium, Gutierrizia sphsero- 
cephala and Portulaca pilosa from the Pecos Valley, Mew Mexico. He 
furthermore isolated it twice from Roquefort cheese. Dogs were used 
in inoculation experiments. In discussing the results of this work the 
author concludes that “the preceding experiments are far from being 
decisive in establishing B. lactimorbi as the etiological factor in the 
production of milksickness. The organism either loses its pathogenicity 
very rapidly when grown on artificial media, or the virulence of the 
