VOL. LXXVI.J^ PHILOSOPHICAL TRANSACTIONS. 121 



was fully equal to that of an adult, consisting chiefly in a thickening of its various 

 muscular fibres*. The peritoneal coat, now become its internal surface, was 

 every where highly inflamed, but not black as on the outside, the inflammation 

 gradually increasing from the band to the extremity of the caecum. Through 

 the whole length of its cavity was included a portion of the ileum uninverted, 

 with its connecting mesentery, which communicated with the larger aperture 

 above described at the extremity of the caecum, and with the arch of the ileum 

 above the band. It was contracted in size, but was nearly free from thickening 

 or inflammation ; some adhesions only connected it with the coats of the colon ; 

 but the portion above the band was at least 4 times as large, thus resembling in 

 magnitude, as well as occupying the place of the great arch of the colon. Be- 

 sides this intestine, this cavity contained a portion of the omentum continued 

 from that above, passing within the band, and extending half-way to the rectum ; 

 an enlarged cluster of mesenteric glands,, of the size of a pigeon's agg, which 

 just emerged from under the band, and were connected with a portion of the 

 mesentery above ; and, at the lower part, the appendix vermiformis larger and 

 longer than natural, but likewise uninverted, the mouth of the cavity of which 

 formed the smaller opening in the caecum before mentioned. 



As long as the parts had been in this very uncommon situation, the faeces 

 must have passed through the valve of the colon, directly into the very lowest 

 part of the rectum, without ever coming in contact with any portion of the large 

 intestines. And in the last week of the child's life, when a prolapsus frequently 

 happened, the faeces passed directly from the ileum into the night-stool. The 

 arch of the ileum, in default of that of the colon, formed the reservoir for the 

 faeces ; which, with the partial interruption to their passage by the stricture oc- 

 casioned by the band, probably caused its enlargement. But the faeces con- 

 tained in it were of a thinner consistence, and wanted the faetor usually met with 

 in the colon. 



XF'I. New Experiments on the Ocular Spectra of Light and Colours. By 

 Robert Waring Darwin, M. D. ; communicated by Erasmus Darwin, M. D., 

 F.R.S. p. 313. 



Reprinted in Dr. Darwin's Zoonomia. 



* The increased action of these muscles, necessarily attendant on tlieir inverted state, would in^ 

 crease the size of their muscular fibres, as happens in the bladder, when it acts frequently. — Orig, 



VOL. XVI. R 



