86 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ III, I

likely to have occurred. In practice, however, it is not always an easy matter
to come to a decision as to whether the disease has progressed to a stage where
intrathecal medication is called for, and this is particularly so when, as is usually
the case, the subject under treatment does not bear any definite history as to the
date when infection might have been contracted, whilst the examination of the
cerebrospinal fluid—which is the only known method for making sure as to the
presence of parasites in that tract—involves operations which it is hardly possible
to carry out under the conditions obtaining in the field. It would therefore
seem to be a good plan to apply the combined method of treatment to all cases
irrespective of the fact whether such a procedure is warranted by the degree of
infection or not.

The problem of combating equine surra would thus have been finally solved,
were it not for the fact that the technicalities of the method and the prolonged
nature of the treatment (for the full course of treatment entails three injections
at fortnightly intervals) have led more than one field worker in India to apply
to this Institute for advice as to whether the treatment cannot be carried out
by methods simpler than the one recommended at present. The difficulties
of the combined method, as experienced by the field worker, are illustrated by the
following remarks reproduced from a communication recently addressed to this
Institute by an Army Veterinary Officer in India :—

" It is considered almost essential for an operator performing the intrathecal
operation to have one or two reliable men to control movement of the horse's head
which is occasionally responsible for fatalities and in many cases loss of part of the
intrathecal dose, which is very undesirable. The operator may supervise casting
operations and correct flexing of the head into the chest to stretch the atlanto-
occipital ligament, but he certainly cannot do much supervision apart from his
own job, once the needle is nearing the spinal canal. The heavy manual labour
of ' tying up' several animals in succession tends also to make the hand of the
operator unsteady. Therefore the assistance of two or three men familiar with the
work is considered indispensable."

The difficulty of the combined intravenous-intrathecal method would thus
appear to be twofold : one may be described as qualitative, being inherent in the
nature of the operation itself, and the other may be regarded as quantitative,
in view of the multiple injections entailed by the method. The two questions
that call for attention relate therefore to the relative efficacy of the intravenous
and the intravenous-intrathecal method of treatment (using " Bayer 205 " alone or in
combination with other drugs) and also to whether the period of treatment may
not be substantially shortened by reducing the number of injections to one or,
at the most, two, with as short an interval between them as possible. In the