80 MONTROSE T. BURROWS 



The irregularly shaped wandering cells 



These are apparently preexisting tissue cells which wander out 

 singly into the plasma. Their contour is variable, oval, triangular, 

 polygonal or star-shaped. They show the characteristic tension 

 and the slow movement of all the mesenchyme. These cells have 

 been frequentl}^ associated with clots, or parts of clots, where a 

 small amount of fibrin is present. The fibrin network is made up 

 of very delicate fibrillae, surrounding large open spaces. The 

 more extensive wandering of mesenchyme cells has alwaj-s been 

 associated with this type of fibrin architecture. Wandering is 

 characteristic of all these cells, but it is considerably limited in 

 most of the preparations. Another type of cell to be considered 

 at this time grows from a tissue deeply and firmly embedded in a 

 dense clot. These are elongated masses of protoplasm which 

 send out many long cone-shaped processes from their end or along 

 their borders. They grow very slowly, never reaching more than 

 four cell lengths. The boundaries of the individual cells are not 

 as a rule clear and they appear as large multinuclear cells. The 

 progress of cellular growth is apparently hindered by the density 

 of the clot (fig. 13) 



Mesenchyme cells growing in layers 



. These cells comprise a group where growth and 'multiplication 

 are most evident. Their frequent location is on the lower surface 

 of the clot or along the wall of the large open concavities, which 

 appear in the older preparations. The cells appear as closely ad- 

 herent, definitely or indefinitely outlined cells spreading out in a 

 continuous layer from various parts of the tissues. They vary 

 from an oval (fig. 12) to a polygonal foim, sometimes appi caching 

 a spindle shape. The development of this layer is due in part to 

 a wandering out of the pieexisting tissue cells associated with 

 active multiplication by mitotic division. In the early periods 

 of growth or in very thin clots (fig. 3) a single laj^er of these cells 

 is noticed, but after the fourth or fifth day in deeper clots, a layer 

 two or three cells thick has often formed. 



