RED BLOOD-CORPUSCLES. 273 



anything positive for the present in regard to a more detailed arrange- 

 ment, and the views on this subject are somewhat divergent. The two 

 following views are more or less related to each other. According to 

 one view the blood-corpuscles consist of a membrane which encloses a 

 haemoglobin solution, while the other view considers the stroma as a proto- 

 plasmic structure soaked with haemoglobin. This latter view is in accord 

 with the assumption as to an outside boundary-layer. Thus accord- 

 ing to HAMBURGER the stroma forms a protoplasmic net in whose meshes 

 there exists a red fluid or semi-fluid mass which consists in great meas- 

 ure of haemoglobin. This mass represents the water-attracting force 

 of the blood-corpuscles, and besides this it is also considered that the 

 outer protoplasmic boundary is semi-permeable, i. e., permeable to water 

 but not permeable to certain crystalloids. The researches of KOPPE, 

 ALBRECHT, PASCUCCI, RYWOSCH/ and others indicate the presence of a 

 special envelope or boundary-layer, and there is no doubt that the outer 

 layer contains so-called lipoids, such as cholesterin, lecithin, and similar 

 bodies. 



The red blood-corpuscles retain their volume in a salt solution which 

 has the same osmotic pressure as the serum of the same blood, although 

 they may change their form in such solutions, becoming more spherical, 

 and may also undergo a chemical change. Such a salt solution is iso- 

 tonic with the blood-serum, and its concentration for a NaCl solution is 

 approximately 9 p. m. for human and mammalian blood. A solution 

 of greater concentration, a hyperisotonic solution, abstracts water from 

 the blood-corpuscles until osmotic equilibrium is established, hence the 

 corpuscles shrink and their volumes become smaller. In solutions of 

 less concentration, hypisotonic solutions, the corpuscles swell, due to 

 the taking up of water, and this swelling may be so great, on diluting 

 the blood with water, that the haemoglobin is separated from the stroma 

 and passes into the watery solution. This process is called haemolysis 

 (see Chapter I). 



A haemolysis may also be brought about by alternately freezing and 

 thawing the blood, as well as by the action of various chemical substances, 

 which act as protoplasmic poisons. These bodies are ether, chloroform 

 alkalies, bile-acids, solanin, saponin, and also the saponin substances, 

 which have a very strong haemoloytic action, also metabolic products of 

 bacteria, higher plants and animals (snakes, toads, bees, spiders and 

 others) and also bodies occurring in blood serum of normal or immunized 

 animals. 



1 See Hamburger, Osmotischer Druck und lonenlehre, 1902; Koppe, Pfliiger's 

 Arch., 99 and 107; Albrecht, Centralbl. f. Physiol., 19; Pascucci, Hofmeister's 

 Beitrage, 6; Rywosch, Centralbl. f. Physiol., 19. 



