THE ADRENAL SECRETION AND THE HEART. 435 



The manner in which the blood-plasma, whether venous 

 or arterial, is distributed by the Thebesian channels is well 

 shown in a study of the vessels of the heart by Arthur V. 

 Meigs. 14 The extreme paucity of literature on the Thebesian 

 channels has caused them to be overlooked by practically all 

 histologists; that they should be treated as capillaries in the 

 author's paper is, therefore, as normal as it is for text-books 

 to do so. "The capillaries of the human heart," says Dr. 

 Meigs, "differ in two ways from those of other parts of the 

 body: they penetrate the muscular fibers, and some of them 

 are larger than those found elsewhere, and of different ar- 

 rangement. . . . The accompanying illustrations are draw- 

 ings which were made with the camera lucida. They are from 

 sections of two human hearts. The first is from the heart of 

 a negro woman, 40 years old, who died of burns. Some pieces 

 of the organ were preserved in Fleming's solution, and others 

 in 70-per-cent. alcohol, and they were stained in bulk with 

 borax-carmine and imbedded in paraffin. The second heart is 

 that of a man, 30 years old, who died of lead encephalopathy. 

 When the post-mortem examination was made, the heart being 

 still quite fresh, there was injected through each of the two 

 coronary arteries as much as the blood-vessels would easily 

 receive of a solution of 3 grammes of Berlin blue (Griibler's) 

 in 600 cubic centimeters of water. Pieces of the organ of 

 suitable size were at once placed in preservative fluid, some in 

 70-per-cent. alcohol, and others in formaldehyde solution. The 

 tissue was afterward stained in bulk with borax-carmine and 

 imbedded in paraffin. 



"The penetration of the muscular fibers by the capillaries 

 is made perfectly clear by the illustrations; it is shown as well 

 by the injected as by the uninjected heart. The two methods 

 of demonstration supplement one another, because, in injected 

 tissue which has been stained, the blood-vessels and their situa- 

 tion are made very obvious by the contrast of color, but the 

 details of the structure of the walls are obscured by the injec- 

 tion material, while, on the other hand, in the uninjected tissue, 

 the structure of the blood-vessels can be seen with the utmost 

 distinctness. In Figs. 1 to 4 the capillaries are easily recog- 



14 Arthur V. Meigs: Journal of Anatomy and Physiology, Jan., 1899. 



28 



