CONNECTIVE TISSUE. 



235 



vessel. I met with this arrangement most frequently in the older 

 animals. Between the wall of the vessel and that of the bone 



there is always a light, narrow 

 rim, crossed by projections of the 

 neighboringbone-corpuscles,unit- 

 ing with the w^all of the blood- 

 vessel. The rim is absent only 

 when the blood-vessel is overfilled 

 with an injection mass. 



In the compact portion of 

 shaft-bones and scapulae of dogs, 

 cats, and rabbits of middle or old 

 age, I often encountered vascular 

 canals, which were either con- 

 stricted in an hour-glass shape 

 or terminated in points. This 

 condition was positively recog- 

 nizable by the fact that, above 

 and below the vascular canal, 

 layers of bone-tissue (respectively 

 bone-corpuscles) could be brought 

 into focus. Closer examination of 

 such vascular canals in longitud- 

 inal sections, as a rule, revealed 

 the presence of but one blood- 

 vessel. (See Fig. 93.) 



Toward the pointed end the 

 wall of the vessel became thick- 

 ened, as if composed of spindle- 

 shaped corpuscles, between which 

 tne caliber either narrowed sud- 

 denly or gradually, terminating 

 close to a spindle-shaped body. 

 In the caliber of the vessel red 

 FIG. 93. HORIZONTAL SECTION blood-corpuscles were occasion- 

 OF THE SCAPULA OF A GROWN ally present and T repea tedly saw 

 DOG. SPECIMEN DECALCIFIED <* * y 5 . . J 



WITH PYROLIGNIC ACID. [Pun- the injected mass penetrating the 

 LISHED IN 1873.] pointed end. The corpuscle which 



0, capillary blood-vessel, containing a OCCluded the fine point of the VCS- 



55 ^XJSiXZSZSi 



medullary corpuscle, and B, bone-corpus- 

 cle, lioth sprung from the solidified blood- 

 vessel. Magnified 800 diameters. 



sel P roved to be a 



and in the direction of the VCSSel, 



, intprval^ similar formations 

 at intervals Similar 



