Fibroglia Fibrils in the Intestinal Wall of Necturus 

 and their Relation to Myofibrils. 



By 



Caroline McGill, 



Instructor in Anatomy, University of Missouri. 



(With Plate V.) 



Mallory (1903) in a paper entitled "A Hitherto Undescribed Fibril- 

 lar Substance Produced by Connective tissue Cells", has shown that 

 connective tissue cells, in addition to elastic fibers and ordinary col- 

 lagenous fibrils, produce a third variety of fibrils which he terms 

 fibroglia fibrils. These fibrils differ both chemically and morphologi- 

 cally from other connective tissue fibrils. In their staining reactions 

 they very closely resemble the coarse fibrils of smooth muscle. Mallory 

 found these fibrils occurring most abundantly in pathologic growths, as 

 in the connective tissue immediately surrounding the invading epithelium 

 in adenoma of the breast. Here they often tend to form basement 

 membranes. In normal tissue, he found them forming the true base- 

 ment membranes of the kidney tubules, of the sweat glands and the 

 glands and ducts of the breast. They also occur beneath the endo- 

 thelium of arteries and the larger veins. Everywhere, these fibrils are 

 much more numerous in pathologic than in normal tissue. In all new 

 growths where new connective tissue is rapidly forming they are very 

 abundant. For Mallory's methods of staining these fibrils the reader 

 is referred to the original paper in "The Journal of Medical Research": 

 Vol. 10. Mallory thinks that these fibrils are produced by connective 

 tissue cells. This he concludes from the fact that they are most 

 numerous in pathologic lesions where there is an abundance of newly 

 formed connective tissue, Because they arise in connective tissue cells, 



