CHAPTER II. 



OP THE INFLAMMATORY CRUST, OR SIZE. 



I SHALL next proceed to inquire into the formation of the 

 inflammatory crust, or size, as it is called. 



This remarkable appearance is frequently met with in inflam- 

 matory disorders, and is formed by the coagulable lymph's 

 being fixed, or coagulated, after the red particles have subsided. 

 It has indeed been supposed to be formed from the serum of 

 the blood; and an excellent writer on this subject seems in 

 doubt to which of the two it should be attributed (xvin). But 

 that it is formed by the coagulable lymph alone, after the red 

 particles have subsided, appears from the following experiments. 



(xvin.) Schwenke a thought that the huffy coat might be intermediate 

 to the serum and cruor. Gaubius, referred to in the Introduction, says 

 that the serum may be spontaneously converted into fibre, so as to form 

 the buffy coat ; Van Swieten 5 asks whether that part may not be formed 

 from the serum ; Gaber c concludes that the pleuritic crust is the same 

 as the coagulable part of the serum ; and Huxham d supposed that the 

 febrile heat turns the serum into the buffy coat. Haller 6 describes the 

 serum as being spontaneously coagulable, forming the buffy coat of the 

 blood, polypi of the heart, and false membranes. A notice is given in 

 the Introduction of the opinion entertained by many eminent men that 

 the fibrin is not distinct from the serum ; of others that coagulation is 

 owing to an aggregation of the red corpuscles ; and further, that these 

 corpuscles are transformed into fibrin (see Notes I and CXVITI). 



The fact probably is, as Liebig f states, that fibrin and albumen are 

 isomerical substances, that is to say, they may, under certain influences, 

 be suddenly converted into each other, as is the case with starch and 

 sugar, their elements being the same and in the same proportions. 

 The sudden changes in the properties of the blood during its evacuation 



a Haematologia, pp. 157-8, 8vo, Hagae, d Essay on Fevers, pp. 5, 36, 6th ed. 8vo, 

 Com. 1743. Lond. 1769. 



b Comment. Boerhaave, Aph. 384. e Elem. Physiol. t. ii, pp. 125-6 ; Prim. 



c De Humor. Animal. Melanges de Phil. Lin. Physiol. 138, 8vo, Gott. 1780. 



et de Math, de la Soc. Roy. de Turin, f Familiar Letters on Chemistry, p. 80, 

 t. iii, p. 67. 12mo, Lond. 1843. 



