276 The Microscope. 



editor;s. ^ 



DEPARTMENT 



^*7S 



rPHOSE not specially interested in the structure of protoplasm 

 1- would do well, for the present, to omit this department of 

 the magazine. They have been warned in time. 



According to Heitzmann, Klein and several German observ- 

 ers, animal protoplasm is a network of fibrils radiating in all 

 directions through the cell and containing a liomogen* ous fluid 

 within its meshes. This and other inclosures have been referred 

 to in an admirable manner by Professor Kirsch in his valuable 

 series on Cytology ; but a sight of this reticulation within 

 the cell is one that has been most desirable for every micro- 

 scopist, but that to the amateur has been especially diflScult. 

 The appearance of the structure has been repeatedly figured, 

 but the sight of a picture is not to be compared in satisfaction 

 to the sight, although it may be an imperfect one, of the actual 

 object itself. This has heretofore not been an easy task, but 

 through n© discovery of my own it has recently come to my 

 knowledge that there is a common animal in whose intestinal cells 

 this structure of the protoplasm may be observed with compar- 

 ative ease and with lively satisfaction. The animal is the com- 

 mon pill-bug of popular language, the Oniscus murarius of the 

 naturalist, who classifies it among the Crustacea. It is found in 

 abundance under damp boards and deca3dng wood in moist 

 places. In order to see the appearances as described by certain 

 observers, I sought the Oniscus, and in five minutes had gather- 

 ed a dozen. It seems to have received its popular name from 

 its habit of bending itself into a pill-like form when disturbed 

 and touched. A pupil of my acquaintance once carried several 

 pill-like specimens to his teacher as a new and large variety of 

 seed. 



Kill an Oniscus by a few drops of alcohol. Remove the legs 

 to get them out of the wa3\ With fine-bladed scissors slit up 

 the body on the lower or abdominal side. Push awaj^, or care- 

 fully remove, the walls of that part of the body, and the intes- 

 tine will be in plain sight. It is a nearly straight, tubular ves- 



