



TISSUES IN GENERAL. 127 



duce a delicate reticulum throughout the basis-substance. (See 

 Fig. 40.) 



Blood-vessels. Fig. 39 represents an artery from the silver- 

 stained periosteum of a grown dog, in which we recognize 

 that the brown basis-substance of the adventitial connective 

 tissue, the cement-substance between the spindle-shaped muscle 

 fibers, and the cement- substance between the endothelia, are all 

 traversed by light lines, which interconnect the light fields cor- 

 responding to these formations. 



Gold-stains bring to view, in the interstices between the single 

 elements, conical filaments which connect all. The walls of capil- 

 laries of the compact substance of shaft-bones are, by means of 

 filaments, in direct connection with the neighboring corpuscles, 

 both of medulla and bone. These filaments penetrate the space 

 around the hollow protoplasm of the vessel, the " perivascular 

 lymph-space" of authors. 



Muscle-tissue. In continuous layers of smooth muscle, both in 

 the fresh condition and after the gold stain, we see that from 

 each spindle arise numerous spokes, which, after having pierced 

 the surrounding cement-substance, inosculate with the neighbor- 

 ing spindles. In such spindles, especially from the muscular 

 wall of the blood-vessels of the umbilical cord, there is an accu- 

 mulation of living matter which renders the corpuscle nearly 

 homogeneous and highly refractive. In very shining spindles 

 there are no nuclei. Wherever nuclei are seen, they are by 

 means of conical spokes connected with the reticulum of living 

 matter of the corpuscle. 



The examination of living striated muscle from the thigh of the 

 water-beetle (Hydrophilus) or craw-fish (Astacus) shows that 

 the distribution of the contractile or " main" substance varies 

 greatly. In opposition to the conceptions of W. Krause,* V. 

 Hensen,f Th. W. Engelmann,| and others, I adopt the view of E. 

 Briicke, viz., "that the sarcous elements do not exist as solid 

 and unchangeable masses in the living muscle, but are groups of 

 molecules arranged in columns of a varying configuration at the 



* "Ueber den Ban der quergestreiften Muskelfaser." Zeitsehrift f. rat. 

 Medizin, 1868. 



t " Ueber ein neues Structurverhaltniss der quergestreiften Muskelfaser." 

 Arbeiten des Kieler physiolog. Institutes, 1868. 



I " Mikroskopische Untersuchungen iiber die quergestreifte Muskelsub- 

 stanz." Pfliiger's Archiv, 1873. 



"Untersuchungen iiber den Ban der Muskelfasern mit Hiilfe des polar. 

 Lichtes." Denkschriften d. Wiener Akaderaie d. Wissensch., Bd. xv. 



