224 ROULEAUX FORMATION 



piles of money. This phenomenon has attracted a good deal of 

 attention, though less than it deserves, and the exact mechanism 

 by which it is produced is still uncertain. It has obviously some 

 resemblance to agglutination. It is quite conceivable, for example, 

 that an agglutinating serum, when greatly diluted, might act so 

 weakly that the corpuscles might be drawn gradually together, 

 and so approach one another in such a fashion as to form the 

 peculiar rolls, very much as in the orderly deposition of molecules 

 to form a crystal, which occurs when a strong solution of a salt is 

 slowly evaporated, so as to allow the molecular attractions to 

 come into play in a regular fashion. But this is not the case, 

 since, as was shown by Descatello and Sturli, it is not possible to 

 dilute an agglutinating serum with normal saline solution so as to 

 convert it into a rouleaux-inducing one. And according to Lange, 

 an agglutinating serum which has had its agglutinin removed by 

 saturation with corpuscles will still give rise to the phenomenon 

 under discussion. 



Both the corpuscles and the fluid in which they are suspended 

 require consideration in the discussion of the question why 

 rouleaux formation occurs in shed blood, though not in the tissues. 

 Human serum will always cause it, though its potency in this 

 respect varies greatly from time to time in the same person, and 

 also in different individuals (as tested on the same specimen of red 

 corpuscles). This power is quickly destroyed on dilution, being 

 almost always annulled on the addition of an equal quantity of 

 normal saline solution. The roulogenous principle also occurs in 

 human milk, but not or not commonly in that of cows, and is not 

 destroyed by boiling for five minutes. Viscosity appears to play 

 some part of secondary importance, and not clearly defined : 

 solutions of colloids, such as gum or gelatin, may induce it, as 

 was pointed out by Wharton Jones. The roulogenous substance 

 occurs to a very large extent in inflammatory exudates, but not in 

 transudates. 



It is possible that the induction of rouleaux formation may be 

 due to the development of some substance in the serum at the 

 moment the blood is shed, and it is also possible that it may be 

 due to some change in the red corpuscles. It has been shown 

 that biconcave discs suspended in water and smeared with grease 

 will run together in this way, and Brunton has suggested that 

 when the blood is shed some fatty acid is liberated by the action 

 of carbon dioxide. It is also possible that the change which 



