CLOUDY SWELLING 397 



gests that the change consists in a coagulation of the cell proteins, 

 which idea is supported by the similarity of the niicTOscopic changes 

 observed in the cells and the earliest microscopic changes observed in 

 cells after heating gently to about their maximum thermal point. 

 On the other hand, the granules in cloudy swelling are generally de- 

 scribed as being soluble in dilute acetic acid and dilute KOH, which 

 indicates that they are not the result of ordinary heat coagulation. 

 If we bear in mind, however, that cloudy swelling probably does not 

 represent one single change, it may be possible to arrive at some 

 understanding of the chemical changes that occur in the process. 

 Albrecht''^ considers, with good reason, that we may have a granular 

 appearance of cells which is simply an exaggeration of the normal 

 granular structure, and, although it may be observed in tissues mod- 

 erately affected by toxins, or in starvation, or in transitory anemia, 

 the change is still to be looked upon as little more than physiological 

 in response to stimuli and overwork. Such a "cloudy swelling" may 

 also occur in cells in the beginning of autolysis, or simply under the 

 influence of salt solution. If the injury is greater, however, as in 

 profound sepsis, or extreme local anemia, the granules becomes coarser, 

 less soluble in acetic acid and KOH, and droplets resembling "myelin" 

 make their appearance. If the injury is still more severe, true coagu- 

 lation of the granules occurs, and they become insoluble, the fatty 

 droplets become more prominent, and the cell reaches a condition 

 that may with propriety be termed necrosis or fatty degeneration, or 

 both. There is no very sharp line separating necrosis and cloudy 

 swelling, especially if we consider only the changes in the cytoplasm. 

 In the earliest stages the granules are perhaps due, in some cases, to 

 simple aggregation of the colloids, without the development of a true 

 coagulation, and so the granules are still soluble. Possibly bacterial, 

 toxins may also cause soluble precipitates, but this does not appear 

 to have been established. Halliburton has shown that temperatures 

 that may be reached in high fevers can cause turbidity in solutions 

 of cell proteins, and hence heat precipitation may be partly responsi- 

 ble for the turbidity of cells in cloudy swelling, but it is doubtful if 

 the granules thus formed would be soluble in acetic acid. A careful 

 discussion of the character and characteristics of this process is given 

 by Bell,"^ wdio concludes that the term cloudy swelling is sound only 

 as a gross description, since microscopically the cells may be found to 

 show albuminous granules, or fatty metamorphosis or simple edema. 

 When present, the granules are of unknown nature — they are not 

 identical with Altmann's granules, although Aschoff and Ernst^^ 

 both consider that many of them are derived from the mitochondria. 

 An enormous number of granules may be present in the renal cells 



" Verb. Deut. Path. Gesell., 1903 (6), 63. 



'8 Jour. Amer. Med. Assoc, 1913 (61), 455. 



" Verb. Deut. Path. Gesellsch., 1914 (17), 43 and 103. 



