1891.] i Botany. 377 
undissolved granules of the same substance. After it had taken up 
some of these granules the plasmodium was removed to pure water, 
when a vacuole was slowly formed about each granule, in consequence 
of its gradual evolution, These artificial vacuoles differed in no respect, 
except in size, from the natural ones, but even showed, in some cases, 
slight pulsations. They were seen to divide and to fuse with each 
other and with pulsating vacuoles, and were formed even in chloro- 
formed plasmodia. It is evident that these vacuoles cannot be depend- 
ent on a special organ, the tonoplast of De Vries, for their formation. 
Pfeffer considers the hyaloplasm and the granular plasma of the cell 
protoplasm to be essentially the same, and to differ merely in the 
presence or absence of granules of most various composition, some of 
which are foreign substances. He has seen the change from one to the 
other condition, and has observed the formation of vacuoles in both 
granular and hyaline plasma. He considers the existence of a plasma- 
membrane, distinct from the remaining cytoplasm, very probable, in 
view of the peculiar osmotic phenomena presented by the cytoplast. 
It is uncertain whether this membrane owes its origin to a definite sur- 
face stretching or whether the contact of water is also necessary. Vital 
activity does not appear to be essential either to its formation or to the 
manifestation of plasticity in the protoplast.—J. E. HUMPHREY, 
Amherst, Mass. 
Alcoholic Material for Laboratory Work in Systematic 
Botany.—lIt is now generally recognized that laboratory practice or 
field work is indispensable to effective instruction in all the natural 
Sciences, Botany deals with material that is especially adapted to 
training the powers of observation. The translation of the characters 
of a stem, leaf, or flower into appropriate language will give the student 
a habit of careful investigation, as well as facility in description. 
Plants direct from the field are generally considered to be in the 
best possible condition for use in the laboratory. It is a difficult 
matter sometimes, however, to shape courses of instruction so as to 
have plants in flower just at the time when they are needed. During 
the spring there is an abundance ; but in the fall and winter, how shall 
material be provided? To furnish a class of thirty or more from a 
greenhouse is too expensive ; moreover, plants will not always blos- 
- Som in the greenhouse just when desired. The plan is sometimes 
adopted of pressing enough specimens to supply each member of the 
class with a specimen of the species to be studied. There are serious 
objections, however, to this plan. In the first place, specimens col- 
lected in such a wholesale way are not apt to be satisfactory. Al 
