as observed in the Tongue of the living Frog, Toad, tyc. 281 



in the circulation for several moments, and the inertia of 

 several of the fluid columns is overcome. In recognising the 

 influence of muscular action on the circulation, we must not 

 forget that this is merely auxiliary to the great action of the 

 heart, and that it only occurs at irregular intervals. 



The action of the heart itself may be traced into the minu- 

 test capillaries, and even sometimes to the large venous trunks, 

 by the periodical acceleration of the vascular column. I have 

 already described the manner to detect the pulsations of the 

 heart of the frog : I found the average number to be sixty-four 

 in a minute. By counting the acceleration of blood in the 

 artery, these two are found to correspond with great precision. 

 In the same way, by accurately noting the time, we may in 

 most cases observe a similar acceleration in the minute capil- 

 laries, and even in the veins. Miiller has already noticed an 

 oscillating movement in the capillaries, when the animal is in 

 a state of great exhaustion ; but in my experiments I have 

 been able to detect it from the commencement without any 

 impairment of the vital powers. In these instances the num- 

 ber of accelerated movements in a minute is about thirty- 

 eight, and they are synchronous with the contractions of the 

 heart : in the accompanying vein at the same time I have also 

 perceived a slight oscillating movement of the blood. By a 

 little practice the synchronous action of the capillaries and 

 the heart will scarcely ever fail to be perceived. 



3. Corpusculation of Capillaries. — The peculiar manner 

 in which the lymph-globules, or corpuscles, conduct them- 

 selves in the capillaries, when in an organ in a state of irri- 

 tation, has of late engaged much attention. The experi- 

 ments of Mr. W. Addison of Malvern, have greatly contri- 

 buted to show these important functions in inflammation. In 

 the tongue of the frog and toad they may be frequently seen 

 circulating with the red particles in the vessels, down to the 

 minutest capillaries. As it has already been pointed out, 

 these spherules are generally found, when they come in con- 

 tact with the parietes of the vessels, to retain their adhe- 

 rence with greater force than is manifested by the red par- 

 ticles in the like circumstances ; as in fig. 3, where the 

 current was observed to continue for many minutes without 

 displacing the globules near the sides of the vessel. Thus 

 we frequently see a lymph-globule remain in the same place, 

 notwithstanding the current of red particles sweeping and 

 pushing by it. From its globular form we should have 

 expected, a priori, that the contrary would have been the 

 case. The appearance in the larger vessels of these spherules, 

 adherent to their inner surface, has been very aptly compared 



Phil. Mag. S. 3. Vol. 29. No. 194. Oct. 1846. U 



