18W6.J MICROSCOPJCAL .lOURNAL. 278 



nucleus iu the centre of the cell and the strands of proto- 

 plasm runninf^ from it to the protoplasm on the wall. — 

 Watch the strands for Cyclosis. 



Irrigate a water mount with 10 per cent, nitric acid and 

 watch a cell; you will see the protojihism includinjjj the 

 bands shrink away and occupy the centre ol'the cell. Stain 

 another water mount with iodine and by its help locate 

 the protoplasm of the ceil. Mount a portion of Spirogyra 

 which has been preserved in alcohol daring the act of 

 cotijugatioii, locate first ordinary cells, their contents 

 shrunken by the action of" the alcohol. Then find fila- 

 ments in which the cells are connected and study all the 

 different stages in the process of conjugation from the 

 first appearance of the lateral growth to the fusion of 

 these and the transfer of the cell contents from one cell 

 to the other, the formation of the zygospore. Find cases 

 of parthenogenesiis. Can you find zygospores formed 

 between cells of the same filament ? Record all your 

 observation by means of fully indexed drawings. 



18b. Cyclosis. The cyclosis in the protoplasm of a 

 cell can be seen best in the hairs of the stamens of Trades- 

 cantia, but they are visible in similar hairs of other 

 plants, and show well in the leaves of the water-plant 

 Eledone, where the chlorophyll grains are carried in the 

 circulation. A cell should be selected for study and the 

 process watched long enough to enable you to determine 

 the courses of the currents in the various parts of the 

 cell ; drawings should be made indicating the direction 

 of the currents by means of arrows. 



19. OsciLLARiA. — If this alga is at hand, mount and 

 study its filaments, locating the shapes and positions of 

 its cells; but especially studying them to see the move- 

 me/ifs of the filaments. These are both motions of oscil- 

 lation or a lateral swaying, whence its name, and motions 

 in the lona: axis of the filament. 



