224^ 



killed, but in warm, moist air they will live ; and if they fall in 

 a favorable place, that is, where there is proper food for them, 

 they will grow and multiply a thousandfold. But the yeast 

 will not produce amoeba, or the latter pus. The pabulum 

 suitable for the first would kill the last. 



Multiplication of PVhite Blood-corpuscles in Disease. — Next, 

 then, let us consider in what way the multiplication of the 

 bioplasts (masses of germinal matter) of the blood in the capil- 

 lary vessels in disease differs from the process which we have 

 seen occurs in the vessels at an early period of development, 

 and during the winter sleep at all periods of life in hybernat- 

 ing animals, and in man under physiological conditions which 

 cause the blood to circulate very slowly, or to stagnate for a 

 time in the smaller vessels of the body. As Avill be inferred from 

 the remarks made in page 218, 1 do not think that any distinct 

 line of demarcation can be drawn between the physiological 

 and the pathological change. In inflammation, the phenomena 

 above referred to proceed a stage further, which is unquestion- 

 ably pathological. But even if this stage be reached, it by no 

 means follows that the texture involved should not regain 

 its normal condition and the previous healthy state be per- 

 fectly restored. On the other hand, it is quite certain that 

 if the state of things now to be described proceeds to any 

 great extent, destruction of tissue is inevitable and return 

 to the original condition impossible. Repair may follow the 

 injury, but this repair involves serious alteration in structure, 

 with corresponding deterioration in action, without capacity 

 for improvement and without the possibility, under any cir- 

 cumstances, of return to the former state. 



When the circulation through the capillary vessels is im- 

 peded in cases of disease, the blood bioplasts (white blood- 

 corpuscles) multiply, and the capillaries often appear to be filled 

 with them, in which case they closely resemble the vessels 

 of an animal during the early period of its development. 

 This state of things always exists in inflammation, and the 

 multiplication of the bioplasts proceeds to a wonderful extent. 

 The appearances seen are not due simjily to the accumulation 

 of white blood-corpuscles, as some have held, but only partly 

 to this, and mainly, as I pointed out many years ago, to their 

 actual growth and increase. " If in any capillaries of the 

 body the circulation is retarded from any cause, an increase 

 in the white blood-corpuscles invariably takes place. In 

 congestion and inflammation of the vessels of the frog's foot, 

 the number of the Avhite blood-corpuscles soon becomes so 

 great as to impede and ultimately to stoj) the circulation 

 through the vessel. Although the great majority are merely 



