2198 Journal of Applied Microscopy 



the experiments was about 1 gr. per kilogram of the body weight, and of this 

 amount of alcohol over 98 per cent, was oxidized in the body. In these experi- 

 ments the alcohol was more completely consumed than are the nutriments of 

 ordinary mixed diet. The potential energy of the alcohol oxidized in the body 

 was transformed completely into kinetic energy and appeared either as heat or 

 as muscular work, or both. The alcohol was essentially as effective in protect- 

 ing body fat from consumption as were isodynamic amounts of fats and carbo- 

 hydrates. The efficiency of alcohol in protecting body protein was evident, 

 although the results on this point were not entirely uniform with all the subjects. 



R. p. 



Ramsden, W. Some New Properties of Urea. A series of experiments on the action 



Proc. of the Physiol. Soc.,pp. xxiii-xxvi, igo2. , ^ -j u i. l 



■' ^^ ^ of urea on proteid substances has 



brought to light a number of hitherto unknown facts, some of which have im- 

 portant bearings on general laboratory technique. The following are some of 

 the more important results. The presence of urea up to saturation prevents the 

 coagulation by heat of all proteid solutions examined. Globulin, caseinogen, 

 acid, and alkali-albumen, copper albuminate, and even heat coagulated proteids 

 swell up and dissolve in a saturated aqueous solution of urea. Dry gelatin is 

 dissolved at room temperature until 40 per cent, is in solution. Coagulable 

 proteids are converted at room temperature into a substance possessing all the 

 properties of alkali and acid-albumen according as the action of the original pro- 

 teid solution was alkaline or acid. Urea has a marked accelerating effect, 

 greater as the amount increases up to about 10 per cent., upon the digestion of 

 fibrin by pepsin, HCl (.3 per cent. HCl), or by trypsin. In much larger quan- 

 tities it has a retarding influence. " A dead frog placed in saturated urea solu- 

 tion becomes translucent and falls to pieces in a few hours. The ligaments, 

 tendons and connective tissue throughout the body are converted into a clear, 

 soft jelly. The muscles if shaken briskly in water fall completely into individ- 

 ual muscle fibres, which retain their structural features and make admirable his- 

 tological preparations. The cornea swells up and becomes soft, the lens is 

 extruded from the eye on slight pressure. The haemoglobin of the blood is con- 

 verted into a body giving the spectrum of alkaline ha^matin, and which on reduc- 

 tion with ammonium sulphide gives the spectrum of haemochromogen. The skin 

 brushes away with the slightest touch. Nervous tissues become semi-transpar- 

 ent and the nerves readily rupture. Connective tissues of different animals are 

 differently affected. In a saturated urea solution no putrefaction ever takes 

 place." This action of urea on connective tissue makes it a valuable histologi- 

 cal reagent for the separation of a tissue into its individual elements (e. g., car- 

 diac and skeletal muscle fibres, fat cells, etc.). The tissues can be preserved 

 indefinitely in the saturated urea solution, and only requires transference to 

 water for a short time to become stainable by the ordinary methods. 



Various compounds of urea with fatty acids were studied. Further investi- 

 gations regarding the reasons for and method of the influence of urea on pro- 

 teids are being carried on by the author. r. p. 



Bilharz, A. Die Lehre vom Leben. Weis- ^^ extended, purely metaphysical dis- 

 baden (J. F. Bergtnann), pp. xiv and 502, ^ ■' ^ ^ 



M. ID, 1902. cussion of biological problems. 



R. p. 



