1888.] MICROSCOPICAL JOUENAL. 183 



cerned in the activities of the cell in daily life. Thus, of a ciliated-muscle 

 cell, the protoplasm would seem to free the energy used in the motions, and 

 to restore during rest the protoplasm broken down in work, while the nucleus 

 is concerned in the production of two ciliated cells from' one, and the pro- 

 toplasm later is concerned in the growth of the two ciliated cells from the 

 former one. 



It is to be observed that while this answer assigns to each part of the cell 

 some occupation, and one which fits well with the facts, it is only superficial. 

 It by no means satisfies our questions, for it does not in any sense tell us just 

 how or what any one of the parts does. To say that the nucleus presides over 

 reproduction only states its sphere of activity without in the least telling -what 

 it does. The cytologists are all trying in every way to find out the structure 

 preliminary to finding out the use of every part of the cell, but at present they 

 have not reached conclusions which have won universal consent. It is due 

 to the great industry and patience of their difficult researches to say that indi- 

 cations of success in part, at least, are very good, and that the past progress 

 of biology leads us to expect that these facts will also be obtained. 



Protococcus — All elementary study in biology. 



By henry L. OSBORN. 



In the examination of yeast not long since we were studying one of the 

 lowest and simplest members of the plant world. In the specimen now be- 

 fore us we have another of the lowest plants. The plant Protococcus viridis 

 grows almost everywhere and thei-e is no one who cannot find material at 

 this season of the year. The plant forms a vivid green incrustation upon 

 stones and wood, but is most profitably sought growing upon the trunks of 

 trees or on the hemlock boards of fences. Since there are numerous green 

 incrustations growing in such situations, some further description of the 

 naked-eye appearance will be helpful. Protococcus forms a very fine-grained, 

 almost powdery, looking growth wherever it is found, and the green is dark- 

 ish. One plant much higher in organization than Protococcus, growing in 

 much the same way, is the lichen of various form, but usually of a duller 

 grayish green and often flaky or leafy in structure, not a fine powdery dust. 



Another kind of plant common in damp places, on boards and stones, is, 

 on close examination, found to be composed of a sort of felt of fine threads. 

 It is an Alga not at all like in shape to Protococcus. It is quite likely that 

 in the search for Protococcus one or both of the above may be found first. 

 Protococcus is more commonly found upon the north side of the board or tree 

 trunk because so well shaded. It may grow on the south side if well shaded. 

 To find it one should hunt for an unpainted hemlock fence, or for a tree whose 

 trunk is well covered with a fine green coat. With a knife cut oft' a few 

 small pieces of wood or bark bearing the green growth and wrap them in a 

 piece of paper. They may be allowed to dry up without injuring them. 

 When ready to study them, it is well to place them in a damp atmosphere 

 for some little time (24 hours) before the examination, though this is not 

 absolutely essential. Of course one who was uncertain as to his material 

 would do well to collect samples of all the various green incrustaceous 

 growths he could find. 



In studying Protococcus the very simple apparatus required are microscope, 

 watch-glasses, slides and covers, dropping tube and water, blotting-paper 

 and needles. With a needle scrape a very little of the green coating from 

 the bark upon the centre of a glass slide, taking care to remove only the 

 green coat and not to dig below it into the bark itself. When a little of the 



