Congenital Anomalies of the Heart 7 



that many different arrangements have been employed and none 

 seem to be entirely free from objections. It would seem that the 

 ideal arrangement would be one based on the embryological stage 

 at which the developmental disturbance occurred. I believe the 

 first attempt at such a classification was made by Friedeberg 

 (1844), who grouped the anomahes as those belonging to the 

 first stage of development, the second stage, etc. Peacock fol- 

 lowed this idea, but added a class of misplacements after the 

 plan of Breschet (1826). Rokitansky (1875) classified his cases 

 on the basis of developmental stages as far as they were then 

 known and Vierordt (1898) followed the same plan. Keith 

 (1909) carried the same idea somewhat further as the result of 

 recent research in cardiac development, particularly of the infun- 

 dibulum. There are still questions of development which must 

 be cleared up before this plan can be freely applied. There is 

 also the possibility that, with development fully understood and 

 etiological factors less obscure than at present, developmental 

 stages may not seem so important. 



Hershf elder (1913) recognized the difficulty of classifying 

 these cases, but seemed to think that an anatomical basis was most 

 satisfactory. Such a purely anatomical arrangement, though 

 quite complete, does not meet all requirements because among 

 other things it does not take into consideration the relation of 

 individual lesions to each other in the same case. It seems evident 

 that the factors which produce developmental disturbances result- 

 ing in arrest or delayed development of the different parts of the 

 heart may bring about very different conditions not only of the 

 anatomical structure but of function as well, depending on the 

 embryonal stage in which they are active. A classification based 

 on the various complexes which are found in the postmortem 

 room would certainly be most satisfactory from a clinical stand- 

 point but presents great difficulty in examining and explaining 

 developmentally. Abbott (191 5) suggests, what seems to me the 

 best solution of the question, a grouping " on mixed principles," 

 that is, an embryological anatomical basis. I will follow this 

 classification with some unimportant modifications and at the 

 end will give an additional resume of the cases as they are en- 



