416 



BLOOD, MORBID CONDITIONS OF THE. 



Andral* justly remarks, we can draw no definite 

 line of demarcation between the blood and the 

 solids. Physiologically speaking, we cannot 

 conceive that of these two facts which form a 

 single whole, the one can be modified without 

 affecting the other. Since the blood nourishes 

 the solids, they must necessarily be influenced 

 by its state ; and since the solids furnish ma- 

 terials from which the blood is formed, and 

 abstract materials by which it is decomposed, 

 any alteration in the nature or quantity of these 

 must necessarily have its influence on this fluid. 

 Suffice it then to observe that the further we 

 extend our knowledge of pathology, the less 

 shall we feel inclined to admit the exclusive 

 claims either of fluidism or solidism, and the 

 more shall we strengthen our belief that the 

 animal structure is composed of parts, every 

 one of which may not only partake of disease, 

 but, under certain circumstances, become its 

 cause. 



Quitting, therefore, all unprofitable specu- 

 lations on this subject, we proceed at once to a 

 detail of facts, and to such observations in elu- 

 cidation of them as occasion may suggest. 



Blood may be excessive in quantity, thus 

 constituting a state of plethora in which the 

 circulating system is supplied more abundantly 

 than is needed for the due performance of the 

 functions of nutrition and secretion. A ten- 

 dency to accumulation in the capillaries and in 

 the different internal organs is induced, and con- 

 gestion with its consequences, or actual rupture 

 of the bloodvessels, is the result. Drowsiness, 

 vertigo, headache, epilepsy, apoplexy, mark this 

 state as existing in the head ; dyspnoea, and a 

 livid or purple hue of the skin, as affecting the 

 lungs ; palpitation and irregular action w'ith 

 syncope mark the ineffectual struggle of the 

 heart to propel its contents. Haemorrhages from 

 the mucous membranes of the nose, the lungs, 

 or the intestines, are often the consequence of 

 congestion in the vessels which ramify on their 

 surface; while indigestion, torpor, and biliary 

 redundancy, are connected with a plethoric 

 condition of the abdominal viscera. Although 

 the existence of such a state, as deducible from 

 the symptoms just enumerated, as well as from 

 the effect which depletion has in removing them, 

 admits of no doubt, it has, nevertheless, not 

 been made the subject of direct proof. The 

 proportion which the circulating blood, even in 

 a healthy animal, bears to its total weight has 

 not been, and, perhaps, cannot be ascertained 

 with precision. Haller collects together many 

 authorities at variance with each other on this 

 point, and at length comes to the conclusion, 

 " Neque dissimulandum est, obiter haec et vage 

 definiri. Infinita enim procul dubio in ratione 

 sanguinis ad reliquam corporis molem varietas 



est/'t 



Fat men and animals have less blood than 

 lean, old than young ; and yet plethora is 

 oftener found in the former than the latter, 

 obviously on account of the mechanical im- 



* Precis d'Anatomie Pathologique, p. 526. 

 t Elementa Physiologiae, torn. ii. p. 5. 



pediment which the encumbered tissue or the 

 rigid fibre offers to the circulation. 



The state of anaemia, or a deficiency in the 

 quantity of circulating blood, whether induced 

 by natural or artificial causes, is no less detri- 

 mental to health than its excess. Its symptoms 

 are general pallor, weak circulation, languor, 

 syncope with palpitations, oppressed respi- 

 ration, flatulency, general oedema, and, in 

 extreme cases, effusion into all the seious 

 cavities. 



Neither plethora nor anaemia necessarily 

 imply, though they are generally complicated 

 with some morbid change in the blood itself. 

 We therefore pass them over with this slight 

 notice, referring for further information to the 

 excellent observations of Andral, in his work on 

 Pathological Anatomy. 



The circulating blood consists essentially of 

 a homogeneous fluid and red particles, and the 

 former, when removed from the body or from 

 the circulation, separates into a fluid and a solid 

 portion. The solid, when washed and freed 

 from the serum and red particles which are 

 mechanically entangled in its substance, consti- 

 tutes the proximate animal principle called 

 fibrine. The fluid contains water, albumen, 

 oil, animal extractive, and salts, alkaline, earthy, 

 and metallic. 



With the exception of the oil and fatty 

 matter, which, in a healthy state of the blood, 

 do not amount to four parts in a thousand, its 

 constituents are all heavier than water, and 

 something is to be learned by ascertaining 

 its specific gravity. In the information thus 

 gained, however, we are limited to the al- 

 ternative, either that some one or more of these 

 constituents is in a state of excess or of de- 

 ficiency, the proportion of water remaining 

 normal, or that the water itself is either su- 

 perabundant or deficient. 



The specific gravity of healthy blood has 

 been variously stated by different authors. 

 Haller makes it on the average 1,052; Blu- 

 menbach, 1,054 ; Berzelius, from 1,0527 to 

 1.057; Denis, 1,059; but none of these au- 

 thors note the temperature at which it was 

 taken, although, from their manner of ascertain- 

 ing it, there must have been considerable 

 variety in this respect. By experiments which 

 I have often repeated with an accurate specific 

 gravity bottle holding 1,000 grains of distilled 

 water, I find that with that fluid four degrees 

 of Fahrenheit's thermometer corresponds with 

 a difference of '001 of specific weight, water 

 being 1,000. Consequently, if one author 

 states the specific gravity of blood at its circu- 

 lating temperature 98 Fahrenheit, while an- 

 other states it at 60 Fahrenheit, the usual 

 standard, the former will make it -0095 lighter 

 than the latter. 



The heaviest blood of which I find a record 

 among my own observations was that of a man 

 suffering under diabetes mellitus. At a tempe- 

 rature of 87 Fahrenheit it was of specific gra- 

 vity 1-0615, while that of the serum was under 

 the average standard of health, namely, 1-027 

 at 60 Fahrenheit, and of the medium propor- 

 tion *o the crassamentum, being, after twelve 



