50 THE TONER LECTURES. 



which may, by way of the blood current, have travelled to 

 the thrombus from some distance. 



The question of the genesis of the colorless cells of the blood 

 has for 3'ears called forth the most indefatigable efforts of the 

 most eminent microscopists, and has taxed the genius of the 

 greatest physiologists of the age. Yet we are far from pos- 

 sessing an entirely satisfactory solution of the problem 



It is, however, generally admitted that in the spleen, in the 

 liver, in the lymphatic glands, and, according to some, in the 

 red marrow of bones, the rate of increase of these cells is more 

 rapid than elsewhere. It has, consequently, been claimed that 

 each of those organs has something special to do with their 

 generation. It has also been demonstrated by Striker and by 

 others that the stable cells of the connective tissue may 

 physiologically give origin to cells which enter the lymphatic 

 circulation, and which cannot, by any means at present known, 

 be distinguished from lymph corpuscles. 



The lymph corpuscles themselves have been observed to in- 

 crease during their own proper circulation, and it is generally 

 admitted that whenever the circulation is sufficiently slowed 

 and oxygen is present in sufficient quantity, their self-propaga- 

 tion is by no means infrequent. 



The following obserA'ation constrains me to recognize an 

 additional source of supply, especially very conisiderable dur- 

 ing the existence of inflammation. 



Fig. 11 represents a capillary of the mesentery of a frog, 

 nine hours inflamed and magnified three hundred diameters, 

 afterward amplified, e. Capillary walls. Z. Leucocytes or 

 wandering cells, external to the walls, g. Cells of adventitia 

 swollen and granular. /. Capillary endothelia granular and 

 swollen, their prominent bellies encroaching considerably upon 

 the lumen of the vessel. The arrow indicates the direction of 

 the blood current, a, <f, i. Colorless corpuscles adherent to 

 the walls, d. Is rather firmly bound to the wall b}' means of 



