548 APPENDIX, 



them in the internal Pacchionian glands mixed with granular matter, and 

 the same kind of fibre as exists in most parts of the arachnoid membrane. 

 Their diameter varies from 75,000 to 39,800 of an inch. I have observed 

 on some parts of the arachnoid, in the vicinity of a cluster of these bodies, 

 cavities of a similar shape and size, from which the corpuscles themselves 

 appear to have been dislodged. From this circumstance, as well as from 

 the general aspect of these bodies, they seem to me either to be structures 

 altogether adventitious, or the result of an abnormal deposition in diseased 

 corpuscles. The tendency which they may be observed to have to co- 

 alesce when several smaller ones occur together, evident by the oblite- 

 ration of those portions which seem pressed against one another, and 

 the union of the remote segments to form a single outline enclosing an 

 area whose figure clearly indicates the number of corpuscles which have 

 united to form it, proves them to be something more than mere earthy 

 deposits, such as are sometimes found in the choroid plexuses, or even 

 than mere scrofulous tubercles. Vogel has found bodies similar to these 

 in the choroid plexuses ; in these, and in the pia mater, Dr. E. Harless 

 has also seen them, and given a very minute account of their structure 

 in a number of Muller's Archives, 1845. This author seems to think that 

 their seat is in the arteries, and that they are somewhat allied to ossifi- 

 cation of these structures ; but their occurrence in all parts of the arach- 

 noid, in some of which there are probably no vessels, is opposed to this 

 view." 



Mr. Rainey regards the corpuscles constituting the epithelium of the 

 choroid plexuses as ganglionary, and details his reasons for this opinion ; 

 hese, h owever, cannot be admitted to be decisive on this point. 



" As respects the supply of vessels and cerebro-spinal nerves to the 

 arachnoid, I may observe, that the arteries are few, but rather large, 

 almost sufficiently so to receive a small injection tube ; (I have prepar- 

 ations of these ;) and that cerebro-spinal nerves may be traced into its 

 visceral portion, and, with the microscope, their tubules can be seen run- 

 ning along with the arachnoid fibres, into which they appear, from the 

 gradual loss of their tubular contents, to degenerate." 



Structure of the Striped Muscular Fibrilla. 

 At page 341., doubts were expressed as to the correctness 

 of the view entertained by Drs. Carpenter and Sharpey, in 

 reference to the structure of the striped muscular fibrilla, 

 At that period, the author had not seen any of Mr. Lealand's 

 preparations, on the examination of which the above-named 

 gentlemen founded their opinion ; he has since, however, 

 been favoured by Dr. Carpenter with the examination of his 

 own specimen, and this would certainly appear to bear out 

 fully their opinion of its cellular constitution. 



