134 BIOLOGICAL ASPECTS OF HUMAN PROBLEMS 



provided this disturbance be more than transitory or 

 sufficiently marked to give signs or symptoms. An 

 instructive illustration of the injurious effects of 

 disturbed balance of forces may be drawn from the 

 pathology of inflammation. The white blood cells 

 or leucocytes carry ferments capable of digesting 

 destructively the bodies of bacteria that have been 

 suitably prepared by the action of the blood. These 

 ferments are of such a nature that they would digest 

 the cells of the body itself, were it not for the fact 

 that these cells are protected against this kind of 

 injury by a ferment (called an antiferment) which 

 opposes the action of the ferment carried by the 

 leucocytes. In conditions of local inflammation, 

 the leucocytes may accumulate in one spot to take 

 up invading bacteria, but in doing so they may 

 liberate an amount of ferment that suffices to over- 

 come the protective antiferment which the cells 

 oppose to them. The result of this excess is that the 

 tissue cells, no longer able to balance the action of 

 the leucocytes, pass into solution with the result that 

 an abscess is formed. Another example of a want 

 of balance, resulting in disease, is seen in the singular 

 condition of thickening of the skin, associated with 

 mental hebetude, which physicians call myxoedema. 

 This disorder appears to be entirely due to a defec- 

 tive secretion of certain juices formed by the thyroid 

 gland, the administration of normal thyroid extract 

 leading to the cure of the disease. On the other 

 hand, the thyroid gland may secrete its juices in 



