ABNORMAL FORMATIONS IN THE BRAIN. 
21 
tended with blood, and their vessels varicose, particularly when the 
pia mater has its vessels overcharged. The choroid plexus is also 
sometimes uncommonly pale and exsanguine. This generally occurs 
when considerable effusion of serum has taken place in the ven- 
tricles, # especially when the effusion is connected with debility. 
Sometimes the plexus contains a number of transparent vessels, 
and it occasionally presents a granulated or FLESHY appearance. 
This has been ascribed to a morbidly enlarged state of the glan- 
dular apparatus, with which, in the opinion of some anatomists, this 
structure is naturally provided. Gelatinous tumours about the 
size of a bean, and surrounded by a cyst, have also, though rarely, 
been observed in this situation. Tumours of a cheesy or sub- 
cartilaginous consistence, the size of a pea, are likewise found, in 
some rare cases ; and occasionally these tumours contain ossific 
deposits in their centres. Bony and earthy concretions are still 
more rarely met with in the choroid plexus than in the membranes. 
All these morbid changes have been most frequently observed in 
apoplectic, epileptic, and paralytic cases ; but they have also been 
frequently detected where no particular symptom referrible to the 
nervous system had manifested itself during life.” 
With reference again to the cause of these formations, I believe 
I may safely state, ( that nothing decisive can be stated upon the 
matter. The use of the plexus choroides is principally to furnish 
the serous fluid, which is known to always exist more or less in 
the ventricles during life; but whether this fluid be secreted or 
simply exhaled from within the vessels forming the plexus, is a 
question I am not prepared to decide ; for, with respect to what is 
said relating to its structure and function, all that I can read upon 
the matter is very diffuse and unsatisfactory. If the plexus, how- 
ever, be a gland, then we can suppose, that from some unknown 
cause its function in the present case became changed ; and that, 
instead of the normal secretion, the products I have described were 
produced : but on this supposition even innumerable difficulties 
present themselves, which to state here would not be attended with 
any profitable result; for all that could be advanced would be mere 
hypothesis or bare conjecture. 
In conclusion I may remark, that, with respect to the ultimate 
effect which might have been produced by these growths, had the 
animal continued to live, nothing positive can be said. I believe 
the masses might have gone on increasing in size, and causing 
absorption of portions of the brain for years, without any disturb- 
ance in the cerebral functions manifesting themselves; for “ of all 
the organs of the body, the brain is the most exquisitely and in- 
comprehensively formed, and presents the least intimacy of con- 
