HISTOLOGY. 



BY DR. E. KLEIN. 

 PART I -PREPARATION OF THE ELEMENTARY TISSUES. 



CHAPTER I 



BLOOD CORPUSCLES. 



IN the microscopical examination of the blood, we have to 

 do only with the study of the formed elements, namely, the 

 colorless corpuscles and blood disks. 



Colorless Blood Corpuscles. The colorless corpuscles 

 are elementary organisms which are endowed with the power of 

 spontaneous motion. This power belongs to them in virtue of 

 the material of which their bodies are composed. This mate- 

 rial is protoplasm. Theirjnption is of two kinds; it consists of 

 change o form and change of place. The latter results from 

 the former. As movements of this kind are seen in greatest 

 perfection in rhizopods and amoeba?, they are called amoeboid. 



Amoeboid Movements of Colorless Corpuscles. 

 Very active movements are seen in the colorless blood corpus- 

 cles of the newt. The cells are large and easy of observation. 

 It is of the first importance, in beginning our study of them, 

 that they should be placed under conditions which, if not iden- 

 tical with, are not materially different from, those under which 

 they actually exist. The simplest method is the following : 



Take a clean glass slide and an absolutely clean cover-glass, 

 which, as we must use high powers (that is, objectives of which 

 the focal distance is short), must be thin. Take the newt out 

 of the water, dry the tail, cut off its end. If no blood comes, 

 squeeze the organ from the root towards the tip until a drop is 

 obtained. One of two methods may now be used : 1st, let the 

 blood drop upon the middle of the glass slide, and place the 

 cover-glass on it in such a way that one edge rests on it? sur- 

 face, while the opposite edge is supported by the finger or for- 

 ceps. Then let the glass gradually down upon the drop. Or, 

 2 



