246 Dr. Beale Croonian Lecture. [May 11, 



of the network of fine nerve-fibres have often been mistaken for the con- 

 nective-tissue-corpuscles beneath and, in some cases, amongst which they 

 lie ; and as old nerve-fibres, as well as other structures, degenerate and 

 leave behind them what is called " connective tissue," a mistake is easily 

 made unless the preparation be very clear*. In this drawing some very 

 fine nerve-fibres, distributed to a portion of muscle at some distance from a 

 dark-bordered fibre, are represented. 



The distribution of nerves to the muscles of Articulata. 



The highly elaborate and rapid movements of insects would lead to the 

 inference that in them the distribution of nerves to the muscles must be 

 very free. The textures are, however, so very elaborate, and their structure 

 so minute, that the difficulty of demonstration must needs be greatly 

 increased. Kiihne's memoir, published in the year 1860, related to the dis- 

 tribution of nerves to the muscles of Hydrophilus piceus. He represented 

 the nerve as perforating the sarcolemma, and being distributed almost in a 

 brush-like manner to the contractile tissue. Subsequently he thought the 

 nerve was connected with the line of muscular nuclei ; but it was obvious 

 that these were muscular, not nervous nuclei at all, and this view was 

 abandoned. Some other observers have fallen into the same error. Al- 

 though I have examined the muscles of many insects, and especially those 

 of the Hydrophilus, I have been unable to confirm the observations made 

 by some Continental observers. 



For illustrating the distribution of nerves to the muscles of insects, I will 

 select the common maggot, the larva of the blowfly. This insect can be 

 obtained in all countries at almost all seasons of the year. 



By reference to these drawings it will be seen that my conclusions accord 

 in the most important particulars with those arrived at in my earlier investi- 

 gations. The drawing-out of the sarcolemma into a sort of eminence at the 

 point where the nerve commences to ramify over it, is well seen in these 

 two figures. This has been mistaken for a special organ by Kiihne (Nerven- 

 hiigel) ; and it has been inferred that the nerve perforated the sarcolemma 

 at this point. 



In his paper in the ' Comptes Rendus' for November 21, 1864, M. 

 Rouget in part confirms my statements regarding the structure of Kiihne's 

 ' Doyere'schen Nevenhiigel,' and states that, at the Nervenhiigel, the nerve- 

 fibre divides into two fine fibres, which may be traced for some distance, and 

 then terminate. " Leur extremite terminale est le'gcrement effilee ; elle ne 

 presente ni plaques, ni noyaux, ni substance finement granuleuse." 



The structure of these so-called Nervenhiigel in insect-muscles was 

 described and figured by me in a paper, accompanied by several drawings, 

 read to the Microscopical Society on June 1, 1864, and published in the 

 'Transactions ' on October 1, 1864. Although M. Rouget agrees with me 



* This part of the question is considered in ray paper published in the Philosophical 

 Transactions for 1864, page 565. 



