286 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



pressure. It may also be demonstrated that, at least approxi- 

 mately, the nutrition of the heart's walls must vary as the 

 square root of the length of the diastolic period. 12^4, IX., 

 327. 



HAEMOGLOBIN IN THE BLOOD OF DIFFERENT ANIMALS. 



As the result of an inquiry by Quinqnand, in regard to the 

 variations in the amount of haemoglobin in the blood of dif- 

 ferent animals, and under different physiological conditions, 

 the following conclusions are reached: 



1. The progressive diminution in the amount of haemoglo- 

 bin contained in equal volumes of the blood follows, as a rule, 

 the steps of the animal scale. 



2. The blood of young animals contains less haemoglobin 

 than that of adults. A line representing the amount of 

 haemoglobin takes the following course : It falls slightly dur- 

 ing the first few days of extra-uterine life, rises during child- 

 hood, remains horizontal during adult life, and finally falls 

 slowly during old age. 



3. The blood of birds is much less rich in haemoglobin than 

 that of mammals, but the weight of the globules is rather 

 greater in the former than in the latter, though the mamma- 

 lian globules contain only a third of the quantity of albumi- 

 nous material present in those of birds. 



4. As a rule, females have less haemoglobin than males. 



5. The lymph of crustaceans contains four to five cubic cen- 

 timeters of oxygen in 100, whereas ordinary water in the 

 middle of winter, when completely saturated, contains only 

 one cubic centimeter in 100. 21 A, December, 1873, 1245. 



THE CIRCULATION OF THE BLOOD. 



The hydrodynamic laws that come into play in the circu- 

 lation of the blood through the arteries have been elucidated, 

 from time to time, by the use of the sphygmograph, but among 

 the various results obtained by the application of this instru- 

 ment, those recently published by Mr. Garrod, of Cambridge, 

 England, are especially worthy of notice. 



We will preface a short abstract of Mr. Garrod's late in- 

 vestigation by the definition of two terms used by him. The 

 cardiosystole is the interval between the commencement of 

 the contraction of the heart and the closing of the aortic 



