CONNECTIVE TISSUE. 247 



lary spaces. I also occasionally met with club-shaped formations, 

 holding a light, finely granular, or an apparently structureless 

 mass. (See Fig. 100.) 



If several of these club-like formations, whether empty or 

 holding red blood-corpuscles, were crowded together, they 

 assumed the appearance of a cauliflower-like rosette, the same 

 as after perforation of the calcareous wall between two neigh- 

 boring cartilage cavities, when the spindle- or club-shaped forma- 

 tions come next to each other. The solid points or the walls of 

 older formations of this kind became, after a time, hollowed o.ut, 

 and thus a varicose reticulum of blood-vessels arose which, from 

 the very earliest period of their formation, contained red blood- 

 corpuscles. Still later, the newly formed vessels may connect 

 with older blood-vessels, and their contents be taken into the 

 circulation. 



(d) Formation of Bone from Medulla* In newly born pups, 

 the formation of bone-tissue takes place within the medullary 

 tissue from the medullary elements. The bone-tissue appears in 

 the form of trabeculae, which occupy the middle, between two 

 blood-vessels or groups of vessels (see Fig. 86). The basis-sub- 

 stance of the trabecula? is finely striated, and here and there is 

 also indistinctly lamellated. 



The transition of medullary into bone-tissue is demonstrated 

 by the following forms : 



In larger medullary spaces, between two blood-vessels, in the 

 longitudinal section of the bone, we often meet with groups and 

 tracts of spindle-shaped medullary elements. These are either 

 homogeneous, bright, of a yellowish color, or granular, and sup- 

 plied with vesicular nuclei, or they may be without nuclei. They 

 are all separated from their neighbors by narrow rims. In 

 transverse sections these tracts appear as roundish or oblong 

 fields, composed partly of shining and partly of pale granular 

 lumps, which are the cross sections of the spindles. We also 

 encounter similar groups at the borders of already developed 

 bony trabeculae, and their general shape always corresponds to 

 an elongated spindle or a rhomb. 



From these groups the trabeculae arise, by means of a deposi- 

 tion of lime-salts at regular intervals in one portion of the 



* Translated from " Untersuchungen iiber das Protoplasma. IV. Die 

 Entwickelung der Beinhaut, des Knochens," etc. Sitzungsber. d. Wiener 

 Akad. d. Wissensch., 1873. 



