74 Answers to Queries. 
329.—Tracing-Paper.—Paper well wetted with Canada balsam 
dissolved in camphine, and dried; or another kind is made with 
nut-oil, mixed with oil of turpentine. The paper is moistened 
with this mixture and then rubbed with flour. Jack. 
332.—Blood-Corpuscles.—In the /ournal of Microscopy for 
January, 1888, B. O. B. will find a fairly complete answer to the 
first part of his question in the article by Mrs. Alice Bodington, 
““Qn Micro-Organisms as Parasites.” There she quotes pretty 
fully from Sutton, Metschnikoff, Koch, and others, to the effect 
that the colourless blood-corpuscles or leucocytes are the means 
appointed for the destruction within the organism of fungi and 
such invading spores as would prove hurtful to the host wherein 
they take up their residence. With respect to the second part of 
the question, I would suggest, Mr. Editor, that you give a word of 
advice to your printer, who has probably inserted “analysis ” 
instead of “analogies.” There is, indeed, a great analogy 
between the leucocytes and the ameeba, both consisting of proto- 
plasmic masses, apparently without a definite cell-wall, having the 
power of protruding rhizopods from any portion of their sub- 
stance, whether for the power of progression or for seizing food. 
Both live on minute animal or vegetable particles floating in the 
fluid with which they are surrounded, and both have the power of 
selfdivision, in order to form new creatures. ‘To each also 
belongs the power of coalescing with other animals of a similar 
type, so as to form a larger protoplasmic mass. In connection 
with these, attention should be drawn to the foraminifera and 
sponges, which are also protoplasmic masses, having similar 
powers to the amceba, but invested with either a coating of car- 
bonate of lime or of silica. With respect to the Torula the case is 
different, for this organism consists of protoplasm coated with 
cellulose. Like the amceba, it has, however, the power of pro- 
truding a portion of its own mass as a kind of rhizopod, but 
apparently only for the purpose of propagating its species, and 
not for the sake of eating. ‘With respect to the Bacteria, there 
would appear some doubt whether they ought to be classed with 
Ameeba as animals or with ‘Torule as plants. Some certainly 
appear invested with a cell-wall, whilst with others, such as the 
micrococci, it is difficult to make out a trace of such an invest- 
ment, and when their movement and high refractive power are 
considered, they appear to approximate rather to Amoeba than to 
Torula. J. Wea 
333,—Lobster.—Somewhere in the Chemical ews, within the 
last twelve months or so, I have seen a short notice by some 
scientific worker, whose name I forget, of an analysis of the green 
gland of the oyster, in which the author demonstrates the presence 
ope 
