BY DR. KLEIN. 49 



the epithelium with a lancet-shaped needle a process which is 

 much facilitated by the previous steeping in the acid. The 

 preparation is then mounted in glycerin. 



Cellular Elements of the Connective Tissue. These 

 are cither amceboid i. e., migratory cells ; or branched i. 

 fixed cells ; the latter being distinguished further by the union 

 of their branched or simple processes, so as to form network ^ 

 of various densities. 



Amceboid Cells. These are to be found in every form of 

 connective tissue. Normally, they occur only in small num- 

 bers, and are irregularly distributed; but, in inflammation, 

 they are numerous in proportion to the intensit} 7 of the process, 

 their multiplication being sometimes scarcely observable, while, 

 at other times, they are so numerous as to fill up the tissue. 

 Two kinds may be distinguished : the cells of the first form 

 entirely resemble the colorless blood corpuscles i. e., they con- 

 sist of finely granular protoplasm, contain two or more nuclei, 

 exhibit amoeboid movements, and are similar!}- affected by re- 

 agents ; while those of the second form are large, coarsely 

 granular cells, which, like the granular cells of the blood, are 

 characterized by the rounded contour of their processes. The 

 former are to be found in eveiy connective tissue, but the latter 

 are more common in the subcutaneous and submucous tissue, 

 in the intermuscular connective tissue, in the mesentery, in the 

 neighborhood of bloodvessels, in the septa of the subcutaneous 

 lymph sacs of the frog or toad, and in the neurilemma of the 

 larger nerve trunks of the frog. The two forms graduate into 

 each other. 



The method of studying these cells in the living condition 

 consists simply in spreading out thin shreds of connective tis- 

 sue on a glass slide, and mounting them in indifferent liquids. 

 Where the integument is loose, as in the neck of mammalia, etc., 

 it is easy to effect this, by first making a slit in the skin, and 

 then, with curved scissors, snipping away a thin lamella of 

 subcutaneous tissue. In the frog, the tongue may be drawn 

 out and fixed by an assistant, while the operator snips out a 

 portion, so as to obtain a cut-surface, from which a thin la- 

 mella can be readily taken, as above. In either case the lamella 

 must be spread out, without loss of time, and with as little dis- 

 placement as possible, on the slide, and mounted in humor 

 aqueus or fresh serum. Blood corpuscles which exist on the 

 surface of the preparation do not interfere with the object, he- 

 cause the amoeboid cells are to be found in the interstices of 

 the clear transparent fibrillated mass of fibrous tissue. It is 

 somewhat more difficult to demonstrate the migratory cells of 

 the normal cornea. The method is as follows: A frog is held 

 by an assistant in such a way that the bulbus oruli is tense. 

 The mcmbrana nictitans is then drawn back, and the bulb pene- 



