10 LAKE-COLOURED BLOOD. 



If blood be mixed with concentrated gum, and if concentrated salt solution be 

 added to it under the microscope, the corpuscles assume elongated forms 

 (Lindwurm). (Similar forms are obtained by mixing blood with an equal volume 

 of gelatine at 3GC., allowing it to cool, and then making sections of the coagulated 

 mass (Rollett). The corpuscles may be broken up by pressing firmly on the 

 cover-glass. In all these experiments no trace of an envelope is observed. 



5. Preparation of the Stroma Making Blood 



"Lake-Coloured." 



There are many reagents which separate the haemoglobin from the 

 stroma. The hemoglobin dissolves in the serum ; the blood then 

 becomes transparent, as it contains its colouring matter in solution, and 

 hence it is called " lake-coloured " by Rollett. Lake-coloured blood is 

 dark-red. The aggregate condition of the hsemoglobin is not altered, 

 when the corpuscles are dissolved it only changes its place, leaving the 

 stroma and passing into the serum. Hence, the temperature of the 

 blood is not lowered thereby (Landois). To obtain a large quantity 

 of the stroma, add ten volumes of a solution of common salt (1 vol. 

 concentrated solution, and 15 to 20 vols. of water) to one volume of 

 defibriuated blood, when the stromata are thrown down as a whitish 

 precipitate. 



The following reagents cause a separation of the stroma from the haemo- 

 globin : 



(a.) Physical Agents. 1. Heating the blood to 60C. (Schultze); the tempera- 

 ture, however, varies for the blood of different animals. 2. Eepeated freezing 

 and thawing of the blood (Rollett). 3. Sparks from an electrical machine (but 

 not after the addition of salts to the blood) (Eollett); the constant and induced 

 currents (Neumann). 



(b.) Chemically active Substances produced within the Body. 4. Bile 



(Hiinefeld), or bile salts (Plattner, v. Dusch). 5. Serum of other species of 

 animals (Landois); thus dog's serum and frog's serum dissolve the blood-corpuscles 

 of the rabbit in a few minutes. 6. The addition of lake-coloured blood of many 

 species of animals (Landois). 



(c.) Other Chemical Reagents. 7. Water. 8. Conduction of vapour of 

 chloroform (Bottcher); ether (v. Wittich); amyls, small quantities of alcohol 

 (Rollett); thymol (Marchand); nitrobenzol, ethylic ether, aceton, petroleum 

 ether, etc. (L. Lewin). 9. Antimonuretted hydrogen, arseuiuretted hydrogen ; 

 carbon disulphide (Hiiuefeld, Hermann); boracic acid (2 per cent.), added to amphi- 

 bian blood, causes the red mass (which also encloses the nucleus when such is pre- 

 sent), the so-called zoold, to separate from the axoid. The zooid may shrink from 

 the periphery of the corpuscle, or it may even pass out of the corpuscle altogether 

 (Briicke) ; Briicke regards the stroma in a certain sense as a house, in which the 

 remainder of the substance of the corpuscle, the chief part endowed with vital 

 phenomena, lives. 11. Strong solutions of adds dissolve the corpuscles; more 

 dilute solutions cause precipitates in the haemoglobin. This is easily seen with 

 carbolic acid (Hiils and Landois; Stirling and Rannie). 12. Alkalies of moderate 

 strength cause sudden solution. A 10 per cent, solution of potash, placed at the 

 margin of a cover-glass, shows the process of solution going on under the micro- 



