SIGNIFICANCE OF PULSE RATE BUCHANAN. 



493 



lowing tables, if they serve no other purpose, at least indicate the 

 sort of value which would attach to a large collection of these par- 

 ticular facts. 



Table I. — Birds. 



Bird. 



Goldlhich 



Canary 



Sparrow 



Greenfinch 



Kingfisher (young) 



Thrush 



Pigeon 



Parrot {Psittacus eriihacus) 



Hen 



Duck (wild) 



Duck (tame) 



Goose 



Average 



weight (in 



grams). 



*16 



20 



24 



26 



*42 



*75 



300 



*430 



1,500 



*1, 134 



*2, 060 



4,400 



Average 

 carbon 

 dioxide 

 per kilo 

 per hour 

 (in grams). 



12.6 



*11.7 



12.2 



11.7 



(?) 



(?) 



3.4 



(?) 

 1.5 



(?) 

 *1.62 

 1.07 



Average 



heart 



weight in 



percentage 



of body 



weight. 



(?) 

 *1.04(3) 



1.36(5) 



(?) 



(?) 

 *2.56(3) 



1.5(5) 



(?) 



.42(6) 

 *1.06(3) 

 . 63C^) 

 *.8(3) 



Average 



frequency 



of beat per 



minute 



when at 



rest. 



*920(6) 



*1, 000(7) 



800(6) 



740(;.) 



*440(7) 



(?) 



185(5) 

 *320(') 



330(6) 



(?) 

 *240(') 



(?) 



The table for birds shows us at a glance that, roughly, the smaller 

 the bird, and therefore the greater the surface relatively to the mass, 

 the larger is the amount of oxygen consumed, or, rather, of carbon- 

 dioxide given off, by a unit of weight in unit time. If the rate of 

 guppl^^ of oxygen to the tissues is greatest, as it ought to be, in 

 those in which the oxidation processes take place most rapidly, we 

 should expect the pulse rates to vary directly with what we take 

 as a measure of these jjrocesses so long as the relative volume of 

 blood expelled with each beat is the same. Since the relative heart 

 size varies, we should expect to find a reciprocal relation between 

 pulse rate and relative heart size dependent upon the rate at which 

 oxidation processes occur. Wliere Ave have these data, or a measure 

 of them, the table shows us that this is the case. Thus, comparing 

 the pigeon and the sparrow, and knowing the pulse rate of the pigeon, 



185X12.2 

 we should expect that of the sparrow to be — w^ — '-■ 



sideration of the diiferent metabolisms, but to be 



:693 m con- 



69^X1.5 

 1.36 '' 



:770 



per minute in consideration also of the different relative weights 

 of the hearts; and this is what it is in some sparrows, though it is 

 lower than what was found to be the average for four sparrows. 

 Again, the hen, which compared with the sparrow, would be ex- 

 pected to have a pulse rate of — ..^ ' z=98.4 per minute in virtue 

 of its size and its metabolism alone, would be expected to have 



