MUSCULAE ARCHITECTURE OF THE HUMAN HEART 213 



The heart muscle problem comes up anew in the great edition 

 of Hildebrand's anatomy by E. H. Weber nearly a century ago.® 

 He also considered the organ as a whole and did not neglect the 

 study of its function, a distinction which has characterized the 

 work of the Leipzig anatomists and physiologists since his time, 

 as the publications of C. Ludwig,io Krehl,ii His, Sr.,12 ^nd His, Jr.^^ 

 bear witness. All this illustrates that progress in anatomy is 

 most likely to occur when its problems include the study of 

 growth and function, as well as of structure. 



Although MacCallum found that he could unroll the foetal 

 pig's heart by macerating it in a modified Krehl's mixture of 

 nitric acid, this is by no means necessary. Hearts that have 

 been boiled in water slightly acidulated with acetic acid are of 

 very great value for the study of the course of the fibers. Un- 

 fortunately this method causes the hearts to shrink — puts them 

 into the systolic state — and softens the tendons at their base. 

 For these reasons I boil only two hours or less or until the outer 

 connective tissue and fat can be easily removed without soften- 

 ing the tendons too much. For careful dissection, however, it 

 is well to have the hearts distended and somewhat tougher than 

 the boiled hearts are. Such specimens can be made by fixing 

 either distended or contracted hearts in a 3 per cent solution of 

 carbolic acid. Specimens prepared in this way may be kept in 

 stock, but their dissection is slow and tedious. The outer con- 

 nective tissue must be stripped off before the muscle bundles 

 may be separated with the forceps and fingers. The disadvan- 

 tage of the carbolic acid is apparent, but I have found that the acid 

 can be washed out in flowing water in the course of several days. 

 Weak alcohol and other macerating fluids are also of value, but 

 since most of the hearts used came from cadavers which had 



9 E. H. Weber, Hildebrand's Handbuch der Anatomie des Menschen. Braunen- 

 schweig, 1831, Bd. 3. 



19 C. Ludwig, Zeit. fiir rat. Med., Bd. 7, lS-19. 



" Krehl, Abhandl. d. K. S. Ges. d. Wiss. Math.-phys. CI., Bd. 17, 1891. 



12 His, Sr., Anatomie mensch. Embryonen, Bd. 3, Leipzig, 1885, and Beitragezur 

 Anatomis des mensch. Herzens, Leipzig, 1886. 



15 His, Jr., Abhandl. d. K. S. Ges. d. Wiss. math.-phys. Classe Bd. 18, 1891. Ar- 

 beiten aus der med. Klinik zu Leipzig, 1894. 



