TUMOURS IN THE BRAIN. 
1G7 
The term immobility has been given to a series of symptoms, 
the principal features of which are — an impossibility of back- 
ing, and a difficulty in adjusting the forelegs, which had been 
previously crossed. By this term, in its fullest meaning, is, 
however, to be understood all those symptoms, whether per- 
manent or intermittent, that derange the general sensations, 
and cause an impossibility or an extreme difficulty of exe- 
cuting muscular movements, whether these movements be 
retrograde or not. This appellation then might remain in 
the nomenclature of the law regulating the return of horses 
for vices ; because it recognizes such symptoms which I con- 
sider to denote the existence of important, and long existing 
lesions of the brain. I have at least always found, in the 
autopsy of horses, whose peculiarities w T ould be better ex- 
pressed by calling them idiots than by giving them the name 
of immobiles , original lesions of various kinds, either of the 
skull or of the viscera which it encloses. I do not mean to 
say by this, that all the chronic lesions of the brain are mani- 
fested by symptoms of idiotism or immobility For example, 
it has been very frequently proved that the presence of choles- 
terine upon the choroid plexus is compatible with appearances 
of perfect health. 
M. Renault. — The position which M. Leblanc occupies 
as a scientific and practical man, renders it necessary that w r e 
should obtain from him an explanation of his opinion of the 
term immobility According to M. Leblanc, every horse which 
is affected w 7 ith a disease of the nervous system that renders 
the execution of movements difficult, whether retrograde or 
not, should be considered as immobile . M. Renault would 
ask if it is thus that M. Leblanc carries out the existing law 
w r ith reference to the return of horses, and whether he would 
condemn as- immobile , a horse which could execute perfectly 
backward movements? The solution of this question appeared 
important to him, because it may have a great influence upon 
the proceedings of veterinary surgeons. 
As to the lesions peculiar to immobility which M. Leblanc 
says he has always rnet wfith in the skull or brain, M. Renault 
has notbeenso fortunate in finding them. Hehas opened horses 
acknowledged to be immobile in which he has found no lesion, 
and, on the contrary, he has met w ith very remarkable lesions 
of the brain in animals w hich, when living, had presented no 
symptoms of immobility 
M. Leblanc. — To the question which M. Renault has 
just addressed to me, whether, wfith the law as it exists, I 
should condemn as immobile a horse which could perfectly exe- 
cute retrograde movements ? I answer, yes ! if notwithstand- 
