140 Chronicles of Science. [Jan., 



substance and globulin contained in the blood. In chicken's blood 

 'the quantity of fibrin obtained is alone much greater than the 

 quantity of fibrinogenetic substance that can be separated from the 

 plasma diluted with a solution of salt of four per cent. Hence it 

 is not possible to doubt that the albuminoid substance of the so- 

 called stroma of the blood corpuscles contributes to the formation 

 of fibrin. These observations of Dr. Heynsius are of very great 

 value, as they tend further to explain the mysterious process of 

 coagulation of the blood, for although the ammonia theory is 

 abandoned, and Schmidt's view of a fibrinogenetic material in the 

 plasma, and a fibrinoplastic one in the corpuscles, has been taught 

 as the best explanation which could be offered of the phenomenon, 

 yet further details were and are still wanting. It appears now 

 that the corpuscles can furnish fibrinogenetic as well as fibrino- 

 plastic substance. 



Whence comes the free Hydrochloric Acid in the Stomach ? — 

 Acid phosphates reacting on alkaline chlorides produce free hydro- 

 chloric acid. In the capillaries of the stomach, distended by en- 

 gorgement, acid phosphates are believed by Professor Horsford, of 

 Cambridge, Mass., to be formed, and thus the free hydrochloric 

 acid produced. By dialytic action the hydrochloric acid is rapidly 

 separated from the inner tissue where it is formed, and coming in 

 contact with the epithelial cells of the gastric tubules, bursts and 

 dissolves some of them, thus forming pepsine, which, together with 

 the acid, some phosphates and chlorides, escapes into the stomach 

 to act in the liquefaction of food. 



Development of Gas in Protoplasm. — Dr. Th. Engelmann has 

 observed in Arcella, a minute protozoon like an Amoeba with a shell, 

 a periodical development of gas. Dr. Engelmann made his observ- 

 ations on specimens confined in a gas chamber, and describes 

 minutely how gradually in the protoplasmic hyaline substance of 

 the animalcule, black points arise, which as gradually coalesce, form- 

 ing a distinct air-bubble. This gas can after a time be absorbed 

 again, and reasons are given for believing that a sort of volition is 

 exercised by the Arcellse in the secretion and absorption of the gas 

 which they use in the manner of a float or air-bladder. The air- 

 bubbles are not connected with the contractile vacuoles or with 

 the nuclei. The air-bubbles, it is important to observe, do not occur 

 in the non-granular protoplasm of the pseudopodia, but in the 

 granular substance, and are not spherical but of an irregular form, 

 which, as Dr. Engelmann observes, proves that the protoplasm is not 

 in the condition of aggregation of a fluid. The chemical composi- 

 tion of the gas thus so remarkably developed by the Arcellse was not 

 determined, nor the mechanism (if any exist) of the formation and 

 disappearance of the air-bubbles. The discovery is of importance 

 from two points of view : in the first place, for the development of 



