522 
ON PRESSURE AS A CAUSE OF ROARING. 
PRESSURE ON THE RECURRENT BRANCH OF THE NERVOUS 
VAGUS, RESULTING FROM AN ENLARGEMENT OF ONE OF 
THE LYMPHATIC GANGLIONS, CONSIDERED AS A CAUSE 
OF ROARING. 
Bj/ the same. 
The following is extracted from an unfinished memoir on pa¬ 
ralysis and atrophy of the laryngeal muscles, originally intended 
for the “ Recueil de Medeciue Vetermaire.” 
“ The causes of this disease may be divided into nervous and 
mechanical. The first may arise either from pressure on the 
par vagum nerve, or on its recurrent branch; from total or 
partial division of either whether by experiment or by acci¬ 
dent ; or from the destruction of their tissue by participating in 
the disease of some contiguous part. 
‘‘ When the atrophy is caused by an interruption of nervous 
influence arising from pressure on the nerves we not unfre- 
quently find that one or more of the lymphatic ganglions is 
enlarged, and that the nerve is involved in the tumour resulting 
from the effusion, and subsequent organization, of lymph which 
has taken place in the cellular tissue enveloping the ganglion. 
The following case appears to be one of this description :— 
“ In the month of May, 1837, I was consulted respecting a 
grey horse, aged nine years. Twelve months before, I had suc¬ 
cessfully treated him for farcy. He was now sent on account 
of a general decline of health. He was much emaciated, 
sweated on the least exertion, and did not eat more than half 
his rations. Independently of this, he was a most inveterate 
roarer. The owner told me that it was then seven months since 
he shewed the first symptoms of roaring. 
I attended this horse until the end of June, but without the 
least success. He still continued in the same miserable-looking 
state. His owner, impatient at the slow progress of the malady, 
and being tired of keeping an animal which, from its great 
debility, was perfectly useless, ordered him to be destroyed. This 
was done by the effusion of blood, and the autopsy was made 
with all possible care. 
On examining the contents of the abdominal cavity, almost 
all the lacteal glands were found considerably enlarged, and one 
of them to such an extent that it formed a tumour weighing 
between six and seven pounds. One of the lymphatic ganglions 
environing the pelvic region was also of an enormous size. 
