STRONGYLUS TETRACANTHUS AND STRONGYLUS ARMATUS. 261 
that the virulent agent of contagious peripneumonia is an 
ordinary microbe ; second, that this microbe is the pneumo¬ 
bacillus liquefaciens bovis. 
STRONGYLUS TETRACANTHUS AND STRONGYLUS ARMATUS 
AS A CAUSE OF DEATH. 
By George Ditewig, D.V.S., Canton, Ill. 
(A Paper read before the Illinois State Veterinary Medical Association.) 
In this paper I shall endeavor to recite my experience and 
observations while treating a small herd of colts that were 
seriously afflicted with the parasites, strongylus tetracanthus 
and strongylus armatus. I do not presume to advance new 
facts or theories in regard to these parasites, but trust that 
the history of the cases mentioned will prove interesting from 
the fact that both parasites were present in such great num¬ 
bers. 
To give a detailed description and complete life history 
of the parasites would require some time, so I will not tire 
you with them ; besides, you are doubtless more or less 
familiar with them. But to refer to them briefly will be in 
order. The strongylus tetracanthus is one of the small nem¬ 
atodes found in the intestines of the horse. The female is 
larger than the male, the length varying from one-fourth to 
three-fourths of an inch, depending upon sex and development. 
The more fully developed worm is of a bright red, the smaller 
a dirty gray or brownish color. The body is slightly taper¬ 
ing anteriorly, and are found in the caecum and colon. 
Life-segmentation of the ova takes place in the uterus; 
they are laid in the intestines of the host, from whence they 
are expelled with the faeces. If the conditions in the external 
world are favorable, they will hatch out in a few days; if at 
this time thev enter into the body of the host, they will 
encyst themselves in the mucous membrane of the large 
bowels, until sexual maturity is attained, when they leave the 
membrane and enter the alimentary canal. 
Strongylus Armatus (The Armed Sclerostome or Palisade 
