Dr. J. E. Gray on Museums and their Uses. 283 



obtained with larvae of a Dyticide (probably of the genus Colym- 

 betes) appear to me to prove that in insects the respiratory 

 movements are not, as in the Vertebrata, dependent on a special 

 focus of innervation. On the contrary, each abdominal ganglion 

 is a focus of motor}' innervation, and takes its part in the per- 

 formance of the respiratory act in its totality. It is also im- 

 portant to remark that, after the section of the nervous chain, 

 the isolated action of a ganglion appears to be weaker in pro- 

 portion as this ganglion is united with a smaller number of 

 other ganglionic elements. 



Thus we see that in this case experiment only confirms what 

 anatomy might lead us to foresee; for when we consider the 

 distribution of the nervous element in the segments of the thorax 

 and abdomen in the Articulata — when we see, in the Crustacea, 

 the respiratory apparatus occupying the most diverse positions, 

 sometimes on the thorax, sometimes on the abdomen, and re- 

 •j; its nenes from the most different points, it is hardly 

 , 'j|e to assume that in insects there is a single focus of in- 

 nervation for the respiratory function. 



XXXV. — On Museumif their Use and Improvement, and on the 

 Acclimatization of Animals ; being the Address delivered to the 

 Zoological and Botanical Section of the British Association, at 

 the Bath Meeting, by Dr. J. E. Gr.\v, President of the Section. 



Before entering upon the special business for which the Section 

 has been called together, viz. the consideration of the Reports to be 

 presented upon various zoological and botanical subjects, and the 

 reading of the papers submitted by the members, I should wish to 

 make a few general observations on some topics which appear to me 

 to have an important bearing on the science which we study, in the 

 hope that they may elicit some observations from the members pre- 

 sent. I have always felt that one of the most important uses of the 

 Association was the bringing together of so large a body of men 

 engaged in kindred pursuits, and the consequent promotion of free 

 personal intercourse between those who, not inhabiting the same 

 locality or even the same country, were scarcely likely to meet except 

 on such an occasion as the present. In such meetings the free 

 interchange of thought by means of oral communication is most 

 valuable ; for it is in this way that facts are most readily brought 

 into notice, and opinions most freely canvassed, that truth is most 

 efiFectually elicited, and that erroneous or crude ideas are dissipated, 

 corrected, and improved. 



Some of my predecessors in this office have given a summary 

 resume of the recent progress of science in the departments over 

 which I have now the honour to preside, and I had at first thought 

 of attemptbg to follow their example ; but I find myself precluded 



