32 Mr M. C. Potter, On the Structure of the Ice Plant. [Nov. 12, 



their activity by dialysis. Again Schmidt says 1 that his ferment 

 solutions, although they begin to be less active if heated to 55° C, 

 and are materially deteriorated if heated to 70° C, require to be 

 boiled for 5 — 10 minutes in order that their active properties may 

 be entirely destroyed ; the ferment body as prepared by the authors 

 loses its active properties if heated to 70° C. 



To account for the results obtained by Gamgee the authors 

 pointed out that when ' washed blod-clot' is treated with 8 per cent, 

 solution of sodic chloride, not only does the ferment body go into 

 solution, but also a considerable proportion of ordinary globulin. 

 This extract was apparently assumed by Gamgee to contain the 

 ferment only and hence his results. Some other facts were also 

 discussed in the communication, such as the apparent greater 

 solubility of the ferment body in solutions of common salt, or as 

 the authors prefer to consider it, the greater readiness of its ex- 

 traction by such saline solutions from precipitates with which it 

 has been carried down. Analogous cases were pointed out, such 

 as the extraction of an amylolytic ferment from the alcoholic 

 precipitate of liver extracts, and of 'rennet' from the mucous 

 membrane of the calf's stomach or from the seeds of a certain 

 plant. 



The authors finally showed that ferment solutions of great 

 activity can be prepared from ordinary fibrin, not differing so much 

 in this respect from the similar extracts of ' washed blood-clots' as 

 might have been expected from the statement made by Gamgee 

 that they are ' much weaker.' 



(3) On the Structure of the Ice Plant (Mesembryanthemum 

 Crystallinum L.). By M. C. Potter, B.A., St Peter's College. 



Mesembryanthemum Crystallinum, known as the Ice Plant, has 

 obtained its name from the circumstance that its stem and fleshy 

 leaves appear as if covered with minute drops of frozen water. 

 This appearance is caused by numerous vesicles on the stem and 

 leaves which are tensely filled with a clear colourless cell sap. 



These vesicles, as described by M. Martinet 2 , are of various 

 forms, generally spherical on the upper surface of the leaf, ovoid on 

 the lower, and elongated at the apex. Each vesicle arises as the 

 outgrowth of a single epidermal cell, and has its apex pointed like 

 the neck of a bottle, caused by the epidermal cell growing out- 

 wards when the vesicle is first formed, and by this part not be- 

 coming rounded off, when the vesicle afterwards increases in size. 



1 Pfliiger's Arch. Bd. vi. (1872) S. 463. 



2 J. B. Martinet, "Organes de secretion des ve'ge'taux." Ann. des Sci. Nat., 5th 

 Series, Vol. xiv. 1871. 



