AUTHOR’S ABSTRACT OF THIS PAPER ISSUED 
BY THE BIBLIOGRAPHIC SERVICE, APRIL 17 
THE FORMATION OF THE CARDIAC LOOP IN THE 
CHICK 
BRADLEY M. PATTEN 
Laboratory of Histology and Embryology, School of Medicine, 
Western Reserve University 
TWO TEXT FIGURES AND THREE PLATES 
INTRODUCTION 
Most of the numerous investigations concerning the develop- 
ment of the heart in birds have dealt either with the very early 
phases of its establishment or with the relatively late steps of 
its division into chambers. The intervening process of loop 
formation, although it is in a general way familiar to embryolo- 
gists, has received much less attention. When I had occasion 
to consult the literature for a discussion of the subject, I was 
unable to find any connected account with adequate figures. 
It has, therefore, seemed worth while to extend and publish 
some observations on cardiac-loop formation in the chick which 
were originally made in the course of other work. 
Records of investigations of the development of the chick 
heart appear in some of the earliest works on embryology. The 
observations on the heart recorded in such classics as those of 
Malpighi (1686), Wolff (1759), von Haller (1767), and Pander 
(1817), though all of them are remarkable for their time, are at 
present chiefly of historical importance. An interesting summary 
of the work of these writers appears in the paper of Lindes (’65). 
The early stages in the establishment of the chick heart have 
since been dealt with by Afanassiev (’69), Gasser (’77), Duval 
(89), His (00), Riikert and Mollier (’06), Graper (’07), Func- 
clus (’09), Hahn (’09), Miller and McWhorter (’14), and Reagen 
(15, ’17). Since this work has been summarized from the mor- 
phological point of view by Lillie (’08), and from the experimental 
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THE AMERICAN JOURNAL OF ANATOMY, VOL. 30. NO 3 
