FATTY DEGENERATION 493 



metals, j)h()sj)h()rus, potassium cyanide, oxidation processes arc 

 inhibited and acids accunndate. The first \isible change after 

 the inhil)ition of oxidation — general or local — is a " softening " 

 of the tissues concerned. If water is available the involved cells 

 swell and become cloudy accompanied or followed by a " yellow- 

 ing " and the appearance of fat globules. The cells then tend to 

 shrink and liquefy. These changes can be mimicked by the 

 addition of a trace of acid to an oil-in-protein enudsion. The 

 enudsifying colloidal proteins, under the influence of acid, develop 

 an increased capacity for the ind>ibition of water. If water is 

 available, the proteins swell and become extremely dilute and the 

 emulsion is broken. The " groi/ing " or cloudiness is due to the 

 presence of colloids (globulins ?) which become less hydrated in 

 an acid solution. The hydration of the one class of colloids and 

 the dehydration of the other class leads to " cloudy swelling.'''' 



The breaking of the emulsion sets free the fat which is present, 

 though normally invisible, in all cells. The tissue becomes yellow, 

 and, as the pathologists say, " fatty degeneration " has become 

 apparent. It must be understood that the fat made manifest 

 by this process existed previously in the cell masked by its associa- 

 tion with proteins, etc., in the enudsion. Its appearance at this 

 stage of dissolution is not due to the conversion of protein or any 

 other cell-constituent into fat as the name " fatty degeneration " 

 might suggest. Careful analysis has shown that the total amount 

 of fat in the cell has not increased. 



As an emulsion has a much higher viscosity than its consti- 

 tuents, one might expect that the breaking of the enudsion woidd 

 lead to a decrease in viscosity or softening of the tissue concerned. 

 Further changes take place which make this loss of rigidity more 

 marked and cause the ultimate dissolution of the protoplasm. 



Almost coincident with the cessation of respiration, the endo- 

 enzymes begin to accelerate the processes of hydrolysis of the 

 tissues (p. 121). Under sterile and anaerobic conditions, the tissues 

 may be con^'erted into an almost odourless fluid — a process termed 

 autolysis. Proteins are broken down to their constituent amino 

 acids and, if autolysis is carried on sufficiently long, some of these 

 acids may be destroyed. Instead of fat, autolysed tissue contains 

 fatty acids and soaps. This self-digestion is a consequence of the 

 lack of free oxygen in the tissues, Avhich lack, as we have seen, 

 causes the accumulation of acids. It has been shown that a very 

 slight increase in hydrogen ion concentration so alters the tissue 

 constituents that they are readily acted on by cellular enzymes. 



In Chap. X. we mentioned the interesting fact that the enzyme 

 which hydrolyses maltose builds up another carbohydrate, iso- 



