POPULAR SCIENCE REVIEW. 
together of these, the delicate filaments forming Leptothrix 
biiccalis are evidently produced ; and these, according to him, 
by further development, pass into Penicillium crustaceum, 
AVhy the molecules should sometimes arrange themselves in 
long rows, and at others into rounded masses (compare fig. 1,/ 
and fig. 5, a), is probably dependent on varying degrees of 
limpidity and viscosity. But why both these forms of molecular 
matter should sometimes possess an inherent power of contrac- 
tility, and at others not, it is impossible as yet even to surmise. 
But, on the determination of this point, the variations existing 
between the different kinds of fermentation and putrefaction 
are evidently dependent. 
