76 Circulation in Chara. 



There is no septum in the tube : which is composed of a cartila- 

 ginous sheath, the parietes of which are thick but hyaline and very 

 transparent. The interior of this tube is lined on each side of the 

 mesian white line by a green membrane with parallel rows of green 

 globules. This membrane may be detached from its adhesion to the 

 sides of the sheath. The least dialysis of this green membrane stops 

 the circulation ; if it continue for some instants after the injury, 

 the fluid circulates around, but does not cross the part deprived 

 of the green matter. The fluid that escapes from the wounded cell 

 coagulates rapidly on reaching the water, but it takes place at least 

 much more slowly if at all in distilled water, one of these -filed tubes 

 placed in water re-produces a covering or incrustation of carbonate of 

 lime : each of the cristals is imprisoned in the cellular interstice of a 

 membrane, which is only the epidermis of the decorticated bark. If 

 a tube that has been scraped &c. be placed in distilled water, no in- 

 crustation takes place. A drop of alcohol, liquid ammonia, caustic 

 alkali or vegetable or mineral acid stops the circulation suddenly. 

 He then states that the circulation is owing to aspiration and 

 expiration or absorption and transudation which keep up constant cur- 

 rents ; but only in the immediate situs of the parietes. Circulation 

 in animals is carried on in the same manner, the composition of 

 the fluid of Chara is exactly like the blood of animals, which he 

 says is homogeneous, the serum and coagulum being formed alike, he 

 says the globules finally disappear in water, the central globule is an 

 optical illusion. He says that the currents of the Vorticella are pro- 

 duced, the ones going to the animal by aspiration, the ones proceed- 

 ing from it by expiration : the ciliee are illusions, depending on the 

 difference of density of the expired liquid. According to him, the 

 tube of the Chara is composed as are all the membranes of vegetable 

 cells, of gum and lime ; the green membrane is albuminous and 

 incloses in its granulations resinous matter. The juice is composed 

 in one of albumen precipitated in globules or dissolved in acetic acid 

 and combined with phosphate of lime, and in the other of ordinary 

 salts of albumen (?) tartrate of potass dissolved in albuminous acetic 

 acid, the hydrochlorates of ammonia, soda and potass. 



These observations were made on the Chara hispida. — See Fig. 3, 

 Plate ii. 



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