314 TR.VNSUDATIONS. 



accumulate in some quantity in the animal body ; as for instance 

 in the moisture of serous sacs, the aqueous humor of the eye, the 

 tears, the liquor amnii, certain dropsical effusions, hydatids, 

 cutaneous vesicles (whether artificially excited or consequent on a 

 skin-disease), or in secretions from the intestinal capillaries, as in 

 the diarrhoea arising from catarrh or drastic purgatives, or accom- 

 panying cholera. 



Those morbid secretions which are consequent on an acute 

 inflammatory process, and are accompanied by laceration of the 

 capillaries and ulceration, have no claim to be reckoned amongst 

 the transudations, seeing that they are not the products of a 

 simple transudation ; these are often very rich in fibrin, but in 

 regard to their general constitution and certain of their consti- 

 tuents, they essentially differ from the simple transudations. 



Like the fibrin, the albumen occurring in transudations is the 

 same as we find in the blood and in other places ; the differences 

 which it exhibits in regard to the character and form of its coagu- 

 lation are entirely dependent on the relations to which we have 

 often alluded, and which are fully discussed in vol. i., pp. 332-334. 

 Thus, in many physiological and pathological transudations, we 

 find that casein-like albumen, which does not coagulate on 

 heating, is precipitated by dilute acetic acid, and separates in the 

 form of a superficial colourless membrane when its solution is 

 evaporated; we need hardly repeat that this body is albuminate of 

 soda, and possesses none of the essential characters of casein. 

 Although casein has been often asserted to be a constituent of 

 such transudations, and has even recently been declared (by 

 Panum*) to be a normal constituent of the blood, I have never 

 succeeded in finding any substance of this nature in such fluids 

 excepting albumen rich in alkali. 



In the normal transudations, as for instance in the liquor 

 pericardii, in the fluids of the cerebral and spinal membranes, the 

 liquor amnii, and all those fluids which contain only little albumen, 

 we can always, with a careful examination, detect albuminate of 

 soda; and the same remark applies to the fluid contained in the 

 bullse of pemphigus, and to the intestinal dejections in cholera. On 

 the other hand, we occasionally, although rarely, meet with 

 transudations from which all the albumen is precipitated on 

 heating, in the form of small flakes ; and those are still more rare 

 which become very turbid on the addition of water, and gradually 

 deposit a sediment of pure albumen ; almost all albuminous 

 * Arch. f. pathol. Anat. Bd. 3, S. 251264. 



