Fibroglia Fibrils in the [ntestinal Wall of Necturu etc. !i] 



he considers them separate and distinct Erom myofibrils. However, as 

 can be shown by tracing the development of smooth muscle, the origin 

 of these fibrils in connective tissue cells is not conclusive in differentia- 

 ting them from myofibrils. 



In the digestive tract of Necturus, just beneath (he lining epi- 

 thelium and scattered in the subepithelial connective tissue, are fibrils 

 which in most respects are strikingly similar to the fibroglia fibrils 

 described by Mallory. In this paper these structures will be called 

 fibroglia fibrils tliough the term, as will be shown presently, is pei ha p- 

 not entirely appropriate. 



The material used was stomach and intestine of Necturus macu- 

 latus. For fixation Zenker's and Gilson's fluids were employed. The 

 material was stained in the following mixtures, Mallory 's anilin-blue 

 connective tissue stain, Van G-ieson's haematoxylin picro-fuchsin mixture, 

 Heidenhain's iron-haematoxylin stain and Weigert's fuchsin-resorciu 

 elastic tissue stain. With Mallory's anilin-blue connective tissue stain 

 the fibroglia fibrils stain uniformly red, as do the fibroglia fibrils of 

 Mallory and as do myofibrils. With Van Gieson's stain they take the 

 intense yellow color characteristic for myofibrils with this stain. When 

 stained with Heidenhain's iron-haematoxylin and counterstained with 

 eosin the appearance varies, depending upon the caliber of the fibril 

 and the amount of extraction of the haematoxylin with the iron-alum. 

 When the sections are over-stained with the haematoxylin and then 

 the stain only moderately extracted, all of the fibroglia fibrils, regard- 

 less of their thickness, stain black. If the haematoxylin be further 

 extracted, the coarser of the fibroglia fibrils stain black while the 

 finer fibrils lose all the haematox3 7 lin and stain red with the eosin. 

 Longer treatment with the iron-alum causes all of the haematoxylin 

 to be removed from the fibrils while the chromatin of the nucleus may 

 still be /well stained. In this instance all of the fibrils stain red. 

 These reactions to iron-haematoxylin are identical with those shown 

 by myofibrils. In fact, with every stain used it was impossible in 

 their reactions with stains to differentiate between the fibroglia fibrils 

 and myofibrils. It is only morphologically that they show any diffe- 

 rences what-so-ever. 



