50 Years Ago

We wish to report new findings which demonstrate that the cytoplasm can be removed from an amœba in a state in which it displays continuous and vigorous streaming in vitro for periods as long as an hour ... The streaming of amœba cytoplasm in the absence of the plasmalemma and ectoplasmic tube as structures completely eliminates the sol-gel or ectoplasmic contraction theory ... The results of the present work provide additional evidence that the endoplasm of the amœba is not a structureless sol, but rather a material which is structurally and physiologically organized and capable of carrying on cytoplasmic streaming at the subcellular level. The partial disintegration of cytoplasm dissociated from giant amœbæ into 'motile units of streaming' provides evidence ... for the fountain zone contraction theory of amœboid movement. Each unit of streaming consists of a U-shaped loop or band of cytoplasm with a bend at which a contraction occurs. The two arms of the loop show a difference of consistency; the contracted or ectoplasmic arm is more rigid. Therefore, when the bend is held stationary and the contraction is propagated in one direction, the cytoplasm of the loop streams through the bend in the opposite direction.

From Nature 10 September 1960.

100 Years Ago

The photograph of the “Leaning” Tower of Pisa in NATURE of August 4 shows clearly that the top tier is not square with the rest. From a rough alignment with the edge of a postcard, the photograph appears as if the tower was of the order of 25 mm./metre out of plumb when the top tier was put on presumably plumb. Exact measures of this and of other parts of the tower might afford interesting data as to the epochs of the construction of the tower and of the progress of its “leaning.”

From Nature 8 September 1910.