256 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [VII, III
in order of preference, in fresh pig-dung, bedding of calf-boxes, horse-boxes and pig-
sties, whereas horse-manure was of inferior importance in this respect. (These obser-
vations are of interest in view of the general belief that M. domestica prefers horse-
manure to any other nidus.) As regards S. calcitrans, the larvae of this species were
of infrequent occurrence in horse-manure, pig-dung and cow-dung, but they bred
chiefly in the bedding of calf-boxes and to a smaller extent in humid remains of straw,
etc., in corners of stables.
The authors also carried out a series of oviposition experiments to determine the
relative attractiveness of pig-dung, horse-dung, calf-dung and cow-dung for gravid
flies, these materials being exposed in jars placed in the open air, pig-sties and calf¬
boxes. In the case of M. domestica, little difference was observed between pig-dung
and horse-manure in their power to attract ovipositing females, for both were highly
attractive. On the other hand, calf-dung was much less favoured as a medium for
egg-laying, while cow-dung did not contain any eggs at all. As regards S. calcitrans,
it preferred horse-manure and calf-dung for egg-laying and only a small number of
eggs were laid in pig-dung and cow-dung. From the results of these experiments
and also from thier general observations, the authors conclude that " calf-stalls in
practice have the greatest production of Stomoxys ". In discussing the possible reason
why S. calcitrans rarely bred in horse-manure in manure-pits, while under experi-
mental conditions they freely oviposited in this material, the authors point out that
the high temperature produced by fermentation in large heaps of manure probably
exercises a deterrent effect on ovipositing flies. As for the absence of Stomoxys larvae
even in manure in horse-boxes, the authors consider this as being due to the fact that
stable-flies, as a rule, concentrate in cattle sheds, where they usually find suitable
material for oviposition and are, therefore, not drawn to horse-manure. [S. K. S.]
Differential diagnosis in plant poisoning. STEYN, D. G. (J. S. Afr. Vet.
Med. Assn. 7, 226-237)
IN view of the existing difficulty in arriving at a definite diagnosis of poisoning
of which the author has had considerable experience in South Africa, an attempt
has been made here to discuss some of the mineral and vegetable poisonings in which
symptoms and post-mortem appearances, similar to those seen in infectious and other
diseases, appear. The author has dealt, in a regular sequence, with the various diag-
nostic criteria as history of outbreaks, symptoms, post-mortem appearances and
histology of lesions. It has been pointed out that a single toxic substance may pro-
duce peracute, acute, subacute or chronic poisoning depending upon the amounts
ingested, and upon the conditions under which poisoning has taken place, thus giving
rise to remarkable variations and even opposite effects on the animal system. That
the symptoms and post-mortem appearances in heavy outbreaks of conical fluke in-
festation in sheep and trichostrongylosis in blackhead Persians may resemble to a re-
markable degree those seen in cases of poisoning by gastro-intestinal irritants is
mentioned.
While the fact of a large number of animals being taken ill or dying at the same
time, severe purging and occurrence of death soon after the drinking of water (as in
Dichapetalum cymosum poisoning) are suggestive of poisoning, the possibility of any
microbic infection should invariably be eliminated by the microscopic examination