132 EXUDATIONS. 



no idea of employing them to designate the internal composition 

 of these objects. A mineralogist might in a similar manner accuse 

 Rokitansky of want of scientific accuracy in applying the term 

 hard to certain new formations, although they are actually softer 

 than the least hard substance in the mineralogical scale of hard- 

 ness. We do not, however, wish to enter the field against those 

 who are entitled from personal acquaintance with pathology and 

 pathological anatomy, and from independent research, to pass 

 judgment on Rokitansky's systematic arrangement and the craseo- 

 logy on which it is based; but we certainly are of opinion that a 

 system cannot be established without the aid of hypothetical modes 

 of conception, and on this account we have adhered to the mode of 

 representation adopted by this experienced and careful observer. 



The fibrinous plastic exudation is the only one which can be 

 easily obtained in a perfectly fresh and tolerably pare state. 

 Fresh wounds afford the best means of obtaining it after the 

 haemorrhage has been arrested, that is to say, when thrombi have 

 formed in the smaller vessels. It can be obtained, however, in 

 larger quantities from animals after portions of muscle have been 

 cut away under the skin, and, consequently, from wounds with a 

 loss of substance. A perfectly fresh exudation of this kind 

 exhibits all the physical and chemical characters of the intercel- 

 lular substance of the blood. The fluid is faintly opalescent, of a 

 sickly taste, alkaline, and in a short time there is a separation of 

 a colourless, trembling, gelatinous mass. Provided the exudation 

 has been obtained perfectly free from blood, which is not always 

 easily accomplished, no morphological elements can be discovered 

 in it besides the fibrin, which coagulates as in fresh blood. If the 

 fluid obtained from the subcutaneous wounds (with loss of sub- 

 stance) is not perfectly fresh, we perceive in about half an hour 

 or an hour granules and nuclei, which constitute the beginning of 

 the suppurative process. These secretions from wounds are there- 

 fore obtained in the greatest purity from animals which are little 

 or not at all prone to suppuration, as, for instance, from birds. 

 Frogs cannot be used for such experiments in consequence of the 

 large quantity of lymph which is poured into the secretion in 

 these animals from the subcutaneous lymphatics. 



The constituents of these perfectly fresh exudations do not 

 differ in quality from those of the liquor sanguinis. The same 

 substances which impede the rapid coagulation of the fibrin of the 

 blood either retard or prevent the coagulation of the fibrin of the 

 exudations (see vol. i, p. 348). The spontaneously coagulated 



