; Botany: 279 
it’ As long as arterial blood is deoxydizing, it will move to the venous 
side, a movement which must continue until the arteries are empty. 
In the same way, in fainting, the blood leaving the arteries, accumu: 
lates on the venous side, and as its flow is dependent on the push of 
the arterial blood entering the capillaries, so soon as no more enters, 
No pressure is exerted in the venous trunks, and if a vein be. opened 
there is no discharge, and under suc hei t 1 hag onc 
cease 
Dr. Draper in the same memoir offers some new views concerning 
the coagulation of blood, which are highly important, but as yet are 
‘not fully established. si oxy inde Be 
os a. V. Botany. | 
“1, Sigillaria and Stigmaria.—Several new examples of the occur- 
‘Tence of Stigmarize as the roots of the trees termed Sigillarie, have 
‘been brought before the Geological Society of London. Mr. Binney 
describes an upright trunk of a Sigillaria with Stigmaria roots fifteen 
feet long, Spreading out into the surrounding clay; the top of the trunk 
terminated in the coal above the bed of clay. It was found in the coal 
at Dunkinfield, in about the same geological position as the one descri- 
bed in Dr. Mantell’s Medals of Creation, at St. Helen’s; from which 
locality it is about twenty-five miles distant. In the Sydney coal-field, 
at Cape Breton, Mr. Brown describes several, and states that upright 
trees with roots (Stigmarise) may be seen in the cliffs near Sydney har- 
bor. It is to be hoped that a specimen will be dug out with the roots 
and stems in conjunction, and placed in some public museum, so as to 
Satisfy the most sceptical; for many eminent geologists still doubt the 
accuracy of the above inferences. 
2. The relations of Noggerathia with living Plants.—The memoir 
on this subject, read by Ad. Brongniart before the French Institute 
On the 29th of December, is inserted in the Ann. Sci. Nat. for Jan- 
Mary last. The plants referred to this genus appear to have contributed 
“ently refers it to the Cycadacer. The memoir closes with the fol- 
ine interesting remark, ‘¢ This genus: being excluded. from the 
being. also removed from the family of Palms to the Gymnospermous 
Vision, and the genus Artisia being. ip the same case, there only re- 
in in certain ancient formations, such vague indications of the pres- 
nce of the great Monocotyledonous division of the vegetable kingdom, 
8 are furnished by several fruits, the structure of which is too imper- 
: fectly known to warrant their being referred with any probability to 
