1894. } Anatomical and Physiological Researches. 71 
drolytic as well as a pectic enzyme. The enzymes of the 
pathogene bacteria are subjects of a great deal of study, and 
much has been written on them. 
Zymogens (‘‘mother of ferment”) are known from the ani- 
mals. They have been found in plants, such as Nepenthes, 
in resting wheat grains, in the irritable cells of Dionaea mus- 
cipula, and in others. 
A discussion of the constitution of the enzymes, the many 
theories with reference to their méde of action, etc., forms 
the conclusion of Professor Green’s solid work.—J. CHRIS- 
TIAN Bay. 
Equiseta in the carboniferous.° 
It is now about nine years since MM. Renault and Zeille™ 
published from the Commentry basin, upper coal measures, a 
description and figure of an Equisetum stem about 12™ long and 
4 or 5™ wide, showing thirteen nodes which are provided with 
unquestionable toothed sheaths in the arrangement character- 
istic of Eguzsetum. This Equisetum Monyi constitutes per- 
haps the first really good evidence of the presence of the 
genus in the carboniferous, though a number of unsatisfactory 
Species of Eguisetites were published years ago by older 
authors. This evidence is now essentially corroborated by 
the description and illustration, by Mr. Kidston, of several 
fructifications which, although the under sides of the hexago- 
nal sporangiferous shields with the sporangia cannot be seen, 
are SO nearly identical in every character with the cones of 
Equisetum limosum Sm. as to leave almost no room for doubt 
aS to the existence of the actual genus as far back in geologi- 
cal time as the carboniferous. The specimens are from the 
shale in the Barnsley thick coal, in the middle coal measures 
of Yorkshire, England.—Davip WHITE. 
The mechanics of growing plants. 
gos Charles Darwin, Krabbe, Clark and others have 
ra t to light many important facts bearing upon the work 
ee by plants in growth and movement, yet to Dr. 
“Fr must belong the credit of the formulation of the gen- 
*Roperr Kinston: ; - 
Ki z ; On the occurrence of the genus Equisetum (2. Heming- 
wm) in the Yorkshire coal-measures. fo and ys N. H.,’ F. 1892. 
Con : 
fossile 2° 30, Patios, 5 Ja 1885. Etudes sur le terr. houill. Commentry.—Flore 
* 394 P/. $7. 7.7. St. Etienne, 1890 
