1892.] Physiology and Pathology of the Mammalian Heart. 435 



the bright ones, it will be a valuable confirmation of my hypothesis 

 as to the causes which produce a new star, namely, the collision of 

 two meteor swarms. On this supposition, the spectrum of Nova 

 Aurigae would suggest that a dense swarm is moving towards the 

 earth with a great velocity, and passing through a sparser swarm, 

 which is receding. The great agitation set up in the dense swarm 

 would produce the dark line spectrum, while the sparser swarm would 

 give the bright lines. 



In taking the first photograph, I was assisted by Mr. Fowler ; the 

 second was taken by Messrs. Fowler and Shackleton. Mr. Baxandall 

 is responsible for the determination of the wave-lengths of the lines, 

 and Mr. Shackleton for the determination of relative velocity. 



II. '* Contributions to the Physiology and Pathology of the 

 Mammalian Heart." (From the Cambridge Pathological 

 Laboratory.) By C. S. ROY, M.D., F.R.S., Professor of 

 Pathology, and J. G. ADAMI, M.A., M.B., Fellow of Jesus 

 College, Cambridge. Received December 31, 1891. 



(Abstract.) 



Our communication begins by stating that we have sought to study 

 the action of the Mammalian heart in conditions (un excised and 

 intact) as nearly approaching the normal as we were able to make 

 compatible with the employment of exact methods of research. This 

 is followed by a general consideration of the difficulties attendant 

 upon such a study, and of the means by which these difficulties may 

 be overcome. 



Under the heading of Methods we describe a cardiometer which we 

 employed to measure the contraction volume and the " output," as 

 well as the changes in the volume of the heart other than those due 

 to its "rhythmic contractions and expansions. A description is also 

 given of the method of employing it, together with a statement as to 

 the degree of the accuracy with which, according to our experience, 

 the instrument supplies information regarding the changes in the 

 volume of the heart. We then describe an automatic counter, which 

 we employed for measuring out and recording the output of the 

 heart, as obtained by the cardiometer. 



This is followed by a description of our myocardiograph, which we 

 made use of to record the contractions and expansions of any part 

 or parts of the ventricular and auricular walls without interfering 

 with the movements of the heart. In most cases we employed this 

 instrument to obtain simultaneous records of the contractions of 

 one auricle and one ventricle. We state also our doubts as to the 



