46 ABNORMAL CONDITIONS OF THE BLOOD. 



when the cord is tied at once, while if it is tied somewhat later it may be . Immediate 

 ligature of the cord may, therefore, deprive a newly-born child of 100 grams of blood. 

 Further, the number of corpuscles is less in a child after immediate ligature of the umbilical 

 cord than when it is tied somewhat later (Helot). 



The methods of Valentin (1838), and Ed. Weber (1850), are not now used, as the results 

 obtained arc not sufficiently accurate. 



Method of Welcker (1854). Begin by taking the weight of the animal to be experimented 

 on ; place a cannula in the carotid, and allow the blood to run into a flask previously weighed, 

 aud in which small pebbles (or Hg) have been placed in order to defibrinate the blood by 

 hating. Take a part of this detibrinated blood, and make it cherry-red in colour by passing 

 through it a stream of CO (because ordinary blood varies in colour according to the amount of 

 O contained in it Gschc idle n, Heidcnhain). Tie a |- shaped cannula in the two cut ends of the 

 carotid, and allow a 0'6 per cent, solution of common salt to How into the vessel from a 

 pressure bottle ; collect the coloured thud issuing from the jugular veins and inferior vena cava 

 until the fluid is quite clear. The entire body is then chopped up (with the exception of the 

 contents of the stomach and intestines, which are weighed, and their weight deducted from the 

 body-weight), and extracted with water, and after twenty-four hours the fluid is expressed. 

 This water, as well as the washings with salt solution, are collected and weighed, and part of 

 the mixture is saturated with CO. A sample of this dilute blood is placed in a vessel with 

 parallel sides (1 cm. apart) opposite the light (the so-called hsematinometer), and in a second 

 Vessel of the same dimensions a sample of the undiluted CO blood is diluted with water from a 

 burette, until both fluids give the same intensity of colour. From the quantity of water required 

 to dilute the blood to the tint of the washings of the blood-vessels, the quantity of blood in the 

 washings is calculated. On chopping up the muscles alone, we obtain the amount of Hb 

 present in them, which is not taken into calculation. 



Quantity of Blood in Various Animals. The quantity of blood in the mouse 

 - Ji t0 A 5 guinea-pig T }. T ( tV to <>V) ; rabbit = ^. T ( T K to ^) ; dog = ^ ( T \ to 

 r y ; cat = rrf - ; birds = ^ to ^ ; frog = ^ to ^ ; fishes = ^ to -Jj of the body- 

 weight (without the contents of the stomach and intestines). 



The specific gravity of the blood ought always to be taken when estimating the amount of 

 blood. The amount of blood is diminished during inanition ; fat persons have relatively less 

 blood ; alter haemorrhage the loss is at first replaced by a watery fluid, while the blood-cor- 

 puscles are gradually regenerated. 



Blood in Organs. The estimation of the quantity of blood in different organs is 

 done by suddenly ligaturing their blood-vessels intra vitam. A watery extract of 

 the chopped-up organ is prepared, and the quantity of blood estimated as described 

 above. [Roughly it may be said that the lungs, heart, large arteries, and veins 

 contain | ; the muscles of the skeleton, { ; the liver, \ ; and other organs, \ 

 {Ranke)] 



41. ABNORMAL CONDITIONS OF THE BLOOD. (A) 1 Polyaamia. (1) An increase in the 

 entire mass of the blood, uniformly in all organs, constitutes polysomia or plethora, and in over- 

 nourished individuals it may approach a pathological condition. A bluish-red colour of the 

 skin, swollen veins, large arteries, hard full pulse, injection of the capillaries and smaller 

 vessels of the visible mucous membranes are signs of this state, and, when accompanied by 

 congestion of the brain, there is vertigo, congestion of the lungs, and breathlessness. After 

 major amputations with little loss of blood a relative but transient increase of blood has been 

 found (0 {plcthura apoccptica). 



Transfusion. Polyamiia may be produced artificially by the injection of blood of the same 

 species. If the normal quantity of blood be increased 83 per cent, no abnormal condition 

 occurs, because the blood -pressure is not permanently raised. The excess of blood is accommo- 

 dated in the greatly distended capillaries, which may be stretched beyond their normal elasticity. 

 If it be increased to 150 per cent, there are variations in the blood-piessure, life is endangered, 

 and there may be sudden rupture of blood-vessels ( Worm Milller). 



Fate of Transfused Blood. After the transfusion of blood the formation of lymph is greatly 

 increased ; but in one or two days the serum is used up, the water is excreted chiefly by the 

 urine, and the albumin is partly changed into urea. Hence, the blood at this time appears to 

 be relatively richer in blood-corpuscles (Panum, Lesser, Worm Miillcr). The red corpuscles 

 break up much more slowly, and the products thereof are partly excreted as urea and partly 

 (but not constantly) as bile-pigmeuts. Even after a month an increase of coloured blood- 

 corpuscles has been observed (Tschii-jcw). That the blood-corpuscles are broken up slowly in 

 the economy is proved by the fact, that the amount of urea is much larger when the same quan- 

 tity of blood is swallowed by the animal than when an equal amount is transfused (Tschirjcw, 

 Laiviois). In the latter case there is a moderate increase of the urea, lasting for days, a proof 



