THE point raised by Mr. Cumming in last week's NATURE (vol. xxxvii. p. 584), as to the use of the words density and specific gravity is, it seems to me, of some importance. For many years past I have, ...

The specific gravities of ten species of helminth eggs were determined using sucrose density gradient centrifugation. Fecal or egg concentrate was layered over a 3 to 54% sucrose density gradient. The ...

Germination and vigor problems in sorghum are usually related to weathering during the post-maturation, pre-harvest period and to drought induced seed immaturity. Weathering and immaturity also lowers ...