693 



may dilate in all its dimensions at one and the same time; costal and 

 abdominal breathing may alternate with one another; costal motion 

 may be undulating or not; and all these may be combined in one, 

 which the author terms " hesitating breathing ;" and lastly, the quan- 

 tity of air breathed is diminished v>'hen there exists pulmonary dis- 

 ease. 



8. " On the Structure and Development of the Liver." By C. 

 Handfield Jones, M.B., Cantab. Communicated by Sir Benjaminr 

 C. Brodie, Bart., RR.S., &c. 



The author gives a detailed description of the structure of the 

 liver in animals belonging to various classes of the animal kingdom. 

 He states that in the Bryozoon, a highly organized polype, it is clearly 

 of the follicular type ; and that in the Asterias, the function of the 

 liver is probably shared between the closed appendage of the stomach 

 and the terminal cfeca of the large ramifying prolongations of the 

 digestive sac contained in the several rays. Among the Annulosa, 

 the earthworm presents an arrangement of the elements of the he- 

 patic organ, corresponding in simplicity with the general configura- 

 tion of the body, a single layer of large biliary cells being applied as 

 a kind of coating over the greater part of the intestinal canal. In 

 another member of the same class, the Leech, in which the digest- 

 ive cavity is much less simple, and presents a number of sacculi 

 on each side, these elements have a very different disposition ; and 

 the secreting cells, although some remain isolated, for the most 

 part coalesce to form tubes, having a succession of dilatations 

 and constrictions, and finally uniting and opening into the intes- 

 tine. In Insects, the usual arrangement is that of long curved fila- 

 mentary tubes, which wind about the intestine ; these, in the meat 

 fly, are sacculated throughout the greater part of their course, till 

 they arrive quite close to the pylorus, where they open ; near their 

 origin they appear to consist of separate vesicles, which become 

 gradually fused together, but occasionally they are seen quite sepa- 

 rate. The basement membrane of the tubes is strongly marked, 

 and encloses a large quantity of granular matter of a yellowish tinge, 

 with secreting cells ; another portion of the liver consists of sepa- 

 rate cells lying in a granular blastema, which cells, in a later stage 

 of development, are seen to be included in vesicles or short tubes 

 of homogeneous membrane, often coalescing and exhibiting a more 

 or less manifestly plexiform arrangement ; this portion of the 

 liver is regarded by Mr. Newport as really adipose tissue. The 

 author has termed it the Parenchymatous portion of the liver, on 

 account of its general appearance and mode of development, though 

 he has not been able to determine whether the tubes aUvays origi- 

 nate from it. Among the Arachnida, the follicular type of arrange- 

 ment prevails; and the same is the case with the Crustacea, the folli- 

 cles in these last being distinctly visible to the naked eye. In Mol- 

 lusca also, we find the follicular arrangement universally to obtain ; 

 yet in certain cases the limiting membrane of the follicles cannot ba 



