595 



"The action of ether and chloroform and that of alkalies seems 

 to throw some light on the natm'e of this membrane. For it is not 

 easy to understand why they should produce their particular etiect 

 unless the membrane was capable of being partly or entirely dissolved 

 by them and this would indicate that it is largely of a fatty nature. 

 Whether it is a pellicle of true fatty substance, or, as is more prob- 

 able, a fat -like material into the composition of which the lecithin, 

 Cholesterin and proteid, which are described as composing the so-called 

 stroma, enter, cannot here be discussed. 



Various other phenomena which have been noticed in connection 

 with the action of reagents and varying external conditions upon the 

 red corpuscles point to the same conclusion viz. that the external 

 envelope of the red corpuscle is composed of a material having the 

 physical characters of fat. A heat of 52'' C causes the coloured cor- 

 puscles to extrude globular processes and beaded filaments, which may 

 attain a relatively considerable length and which eventually break off 

 from the main substance of the corpuscle and form coloured globules 

 in the fluid. A further increase of temperature to 60^ C sets free the 

 haemoglobin and produces the complete disappearance of the corpuscles. 

 Hence we may suppose the fatty pellicle to become softened and 

 eventually completely melted under the action of the increased temper- 

 ature, thus permitting of the partial and eventually of the complete 

 flowing out of its contents. 



Almost any fluid which has a slight solvent action upon fats also 

 causes an extrusion of the haemoglobin,, often with disappearance of 

 all sign of the stroma or membrane: this is the case with solutions 

 of the bile salts. Dilute alcohol in the form of sherry wine has been 

 noticed to produce at first the extrusion of filaments like those caused 

 by heat (Addison); and this may be supposed also to be due to the 

 softening or incomplete solution of a fatty pellicle. The envelopes of 

 the corpuscles ("stromata") after complete decolorization with water 

 or dilute acids, stain faintly, but characteristically of the presence of 

 fatty substance, when treated with osmic acid. Finally the presence 

 of a fatty pellicle would of itself, as above pointed out, furnish a 

 sufficient explanation of the otherwise obscure phenomenon of rouleau 

 formation. 



It has often been urged against the existence of a membranous 

 envelope to the corpuscles that such an envelope when mechanically 

 ruptured, as by pressure upon the corpuscles, should show signs of the 

 gap through which the contents have escaped. This is by no means 

 necessary, however, for in the case of a thin fatty pellicle such as 



38* 



