The Microscope. 55 



toplasm in the onion, I should have given credit for the discovery 

 to Professsor T. J, Buvill. The error was due to an oversight, 

 and I make the correction very cheerfully. 



Other correspondents report that they have foiled to see the 

 movement of the protoplasmic current, and still others that they 

 have not been able to observe the bands and threads that carry 

 the granules, although the granules themselves were visible I 

 think that we all have had the same experiences. Immediately 

 on the receipt of my correspondents' pleasant letters I repeated 

 the experiment, and failed utterly. Even after the onion had 

 been all night in a warm room, not a trace of movement in the 

 protoplasm nor among the granules could be seen. On the con- 

 trary, the colorless protoplasm was massed in little heaps and 

 drops in the angles of the cells and along the sides of the walls, 

 and warming in this case had no eflFect. Another onion that hap- 

 ed to be sprouting, had its protoplasm in the most active move- 

 ment, the motion being almost violent, the colorless material 

 boiling along the walls, and throwing off threads and bands 

 that bent and curved like the living things they were The 

 granules were likewise in great agitation, while they and the out- 

 lines of the protruded threads and of the streams along the walls 

 were plainly visible to an eighth inch homogeneous immersion 

 objective, the particles themselves being as easily seen with a 

 good one-fifth. The edges of the protoplasmic currents can 

 scarcely be observed with a power less than the one-eighth, and 

 then only by an eye somewhat accustomed to the study of mi- 

 nute and delicately defined objects. An Abbe condenser is a great 

 help, but if the condenser is absent, light that is slightly oblique 

 will make the outlines somewhat more prominent. Yet in any 

 event, the margins are very pale and ghostly. 



The phenomenon is a remarkable and an interesting one. It 

 is easily seen after one or two trials and it calls for no compli- 

 cated manipulation. A little intelligent management of the 

 mirror, a good objective of the proper power, a little patience, 

 and some careful attention to the smoothness of the membrane 

 and to the absense of wrinkles, are about all that is needed for 

 a successful view, provided the onion be alive, a fact that, unless 

 the bulb be sprouting, can be known only after microscopic ex- 

 amination. The sprouting onion will probably always show the 

 movements in its cells. 



