160 



CONNECTIVE TISSUE. 



The plastids in the bundles are flat corpuscles, either irreg- 

 ularly scattered or presenting a chain-like arrangement ; these 

 bodies are frequently small, not surpassing the size of nuclei. In 

 the myxomatous portion, however, they are larger, and have 

 coarse offshoots, sometimes directly joining in a stellate form. 



The myxomatous portion 

 may also contain, in a 

 varying number, the " mi- 

 grating cells n of Von 

 Recklinghausen and the 

 coarsely granular " plas- 

 ma-cells " of Waldeyer, es- 

 pecially in the neighbor- 

 hood of capillary blood- 

 vessels. Their significance 

 8 is not yet understood, nor 

 is their presence constant. 

 The delicate bundles, if 

 treated with dilute acetic 

 acid, swell and are con- 

 stricted in such a manner 

 as to give the bundle an 

 hour-glass or rosary-like 

 appearance. These con- 

 strictions are due, accord- 

 FIG. 55. ARACHNOID OF THE SPINAL CORD ing to Henle, to the pres- 

 OP AN ADULT. ence of elastic fibers twined 



around the bundle, which 

 are not acted upon by the 

 acetic acid. Their origin 

 is explicable, as I shall 

 show hereafter, by the formation of territories, a number of 

 which compose the bundle, while at the boundaries of the ter- 

 ritories the basis-substance is solidified into elastic substance. 

 A. Rollett maintains that the elastic fibers are offshoots of cells 

 similar to the reticular variety of connective tissue 5 according to 

 Franz Boll, these cells, originally twined around the bundle in 

 shape of a reticulum, fuse in advancing development into an 

 elastic membrane, which envelops the bundle and exhibits linear 

 thickenings, branching after the manner of veinlets in leaves. 



The best examples of loose connective tissue are the arach- 

 noid and the trabeculae traversing the sub-arachnoideal space. 

 (See Fig. 55.) 



Delicate bundles of fibrous connective tissue, B, 

 run in different directions and contain very small 

 plastids in the shape of oblong nuclei. The inter- 

 stitial basis-substance slightly fibrous. E, a portion 

 of the covering endothelium. Magnified 500 diams. 



