BIOLOGY. . S07 



and that the blood of man, and the mammalia generally, contains 

 from 5 to 6 parts of iron per 10,000 parts of blood. 



Cojjper in the Animal Body. — Dr. G. L. Ulex, of Hamburg, has 

 published the result of extensive researches, showing that copper 

 is one of the most widely disseminated substances in nature. It 

 had been long known that copper existed in the blood of moUusks 

 and others of the lower animals ; but Dr. Ulex found it in mam- 

 malia, birds, batrachians, reptiles, fishes, and articulates also ; 

 in man, the horse, the ox, the lynx, the common fowl, the teal, 

 the tortoise, the lizard, the adder, the frog, the eel, the haddock, 

 etc. He concludes that it is found in the bodies of all animals, 

 and says : " As animals live, directly and indirectly, upon plants, 

 it follows that it must occur in all plants ; and as plants derive 

 their mineral constituents either from the soil or from sea-water, 

 copper must be generally diffused through both these media." 



Mortality of Paris. — As far as can be judged from historical 

 documents, the annual mortality in Paris at the commencement of 

 the last century was 1 in 28 ; 50 vears later, 1 in 30 ; in 1836, 1 in 

 36; in 1846, l^in 37; in 1851, 1 in 88; in 1856, 1 in 39. Those 

 numbers apply to old Paris. In 1860, the time of annexation, the 

 population was increased by the addition of an area less favorable 

 for the health than the intei-ior of Paris. Still, the proportion of 

 deaths in 1861, with 1,696,141 inhabitants, was 1 in 39; in 1862 

 and 1863, it was 1 in 40. 



This improvement in the public health may be attributed to the 

 great works carried forward in the capital, — that is, the opening 

 of avenues, improved supply of water and drainage, the super- 

 vision over crowded and unwholesome tenement houses, and the 

 organization of hospitals ; also to the general prosperity of the work- 

 ing classes, who take better care of themselves, di*ess more warm- 

 ly, and eat more wholesome and abundant food. 



The Sphy gmograph. — This is an instrument invented by Dr. E. 

 J. INIarey, a Paris physician, for producing a self-written record 

 of the swellhigs and contractions of the arteries, known as the 

 pulse. The main features of the instrument are the following : 

 A principal beam, of light construction, is fastened on the arm by 

 carefully-padded straps ; to this is attached a lever of nearly the 

 length of the fore-arm ; the shorter arm of this lever rests gently 

 but firmly on the pulse ; at each rise of the artery and subsequent 

 fall, the motion is exactly imparted to the lever, and the end of the 

 longer arm performs the same movements as does the shorter, but 

 on a much larger scale. To the end of the longer arm is attached 

 a fine-pointed pencil, in contact with which a smooth strip of 

 paper is made to move by clockwork in a horizontal direction. 

 The efiect of this arrangement is that a straio;ht line would be 

 drawn on the piece of paper were it not for the rhythmic perpen- 

 dicular movement caused by the pulse, which results in the pro- 

 duction of an undulated line, the waves in which represent the 

 separate expansions of the artery. It is evident that since the 

 movement of the paper is invariably uniform, the variations in the 

 pulse will be distinctly indicated by the height, length, and form 

 of the waves ; and accordingly we have a most accurate and 



