450 
DE. PETTIGREW ON THE AEEAN GEMENT OE THE FIBRES 
Senac* (1749), Haller! (1757), Wolfe $ (1780-1792), Gerdy § (1823), and Reid || 
(1839). The writings of these investigators, although differing in minor matters, agree 
on the whole, as may be seen by a hasty reference to the more prominent views enter- 
tained by them. As early as 1669, Dr. Richard Lower promulgated the idea that the 
external fibres of the ventricles of the mammal proceed in a spiral direction from left 
to right downwards; the internal fibres proceeding from left to right upwards. The 
fibres, according to this author, are continuous at the apex, and form an imperfect figure 
of 8. In this opinion Lower was followed by Gerdy, who, however, maintained that 
the external and internal fibres make a more perfect figure of 8 than that given by 
Lower, and added that all the fibres of the heart form loops, the apices of which look 
towards the apex of the heart. This idea of Gerdy’s with reference to the looped 
arrangement of the fibres at the apex was combated in recent times by Dr. Duncan, 
jun., of Edinburgh ^[, who says, Gerdy commits a grave error when he asserts that all 
the fibres of the heart form loops the apices of which look towards the apex of the heart , 
since the number of tops (and by this Dr. Duncan means loops) which look in the opposite 
direction , or towards the base , is not less. Adopting the suggestion of Dr. Duncan, it 
follows that the fibres composing the ventricles form twisted loops, which look alike 
towards the apex and the base. Frederick Caspar Wolff furthered the investigation, 
by showing the possibility of dividing the muscular substance composing the ventricles 
into bands; whilst Senac in the last century, and Dr. John Reid in this, gave a new 
interest to the subject, by showing that the fibres of the external and internal surfaces 
of the ventricles are more vertical in direction than the deeper or more central fibres, 
which more approach to the circular. Such are a few of the more important facts ascer- 
tained by successive investigators. 
Having myself in the summer of 1858 made numerous dissections, upwards of 100 of 
which are preserved in the Anatomical Museum of the University of Edinburgh**, I 
have arrived at results which appear to me to throw additional light on this complex 
question, and which seem to point to a law in the arrangement, simple in itself, and 
apparently comprehensive as to detail. This law will be adverted to subsequently. 
Summary of Facts established in the present Memoir. 
The following are a few of the more salient points demonstrated, which the reader 
* Traite de la structure du Cceur, de son action, &c. Paris, 1749. 
t Elementa Physiologic, tom. i. 1757. 
t “ Dissertationes de ordine fibrarum muscularium Cordis,” in Acta Acad. Petropolit. 1780-1792. 
§ Recherches, Discussions et Propositions d’Anatomie, Physiologie, &e. 1823. 
|| Cycl. of Anat. and Phys., article “Heart.” London, 1839. 
IT See extract from Dr. Duncan’s unpublished manuscript, given by Dr. John Reid in Cycl. of Anat. and 
Phys., article “Heart,” p. 592. 
** These dissections obtained the Senior Anatomy Gold Medal of the University, in the winter of 
1859. 
