A COMPARATIVE MICROSCOPIC STUDY OF THE 



INTERCALATED DISCS OF VERTEBRATE 



HEART MUSCLE 



H. E. JORDAN and K. B. STEELE 

 From the Anatomical Laboratory of the University of Virginia 



• TWENTY-THREE FIGURES 



CONTENTS 



I. Introductory 151 



II. Material and methods 152 



III. Descriptive 153 



A. Adult material 153 



1. Monkey 153 



2. Bat 157 



3. Guinea-pig 159 



4. Chipmunk 160 



5. Opossum 162 



6. Humming-bird 162 



* 7. Turtle 162 



8. Toad 162 



9. Frog 163 



10. Trout 164 



B. Young and foetal material 165 



1. Guinea-pig 165 



a. Second, third and fourth weeks 165 



b. First week 165 



c. Last week of gestation 165 



2. Cat of four days 165 



3. Child of four years 165 



IV. Discussion 167 



V. Summary and conclusions 172 



Literature cited 173 



I. INTRODUCTORY 



On the basis of histologic findings in the heart of the humming- 

 bird, Jordan ('11) believes he has demonstrated that intercalated 

 discs are not correctly interpreted as intercellular elements mark- 

 ing cell boundaries, as recently again urged in the papers by 



151 



