1876.] found in Mucus and other Albuminoid Fluias. 141 



columns, in which, however, no characteristic surfaces or angles can be 



discoyered even with the highest magnifying-p owners In the case o£ 



mucus we have an appearance quite similar. The sohdified jelly-like 

 mucus is entirely homogeneous and hyaline ; and only in the direction 

 in which it is stretched, dragged, or torn does it show folds and markings, 

 and, according to circumstances, even a network — an actual division into 

 filaments or bundles. But if it is brought to coagulate by means of 

 water, still better by means of alcohol or acids, the coagulation is fol- 

 low^ed by a shrinking, through w^hich actual fibrils may result"*. The 

 coagulation-appearances now to be described will be found to favour the 

 analogy with crystallization. These exceptional coagulation-forms are 

 also interesting as having recently been mistaken for something quite 

 different. This mistake, which has greatly contributed to the spread of 

 a reactionary and superficial pathology, w^ill be referred to at the end of 

 the note. 



The mucus on which the observations have been made occurred in the 

 acini and ducts of mammary glands of the bitch and cat, in the alveoli 

 of the thyroid body, and in the alveolar spaces of two extensive colloid 

 or myxomatous tumours that grew from bone or periosteum ; the mam- 

 mary gland is known to produce mucus as a normal secretion under 

 certain circumstances t. The same appearances have been found also 

 among the coagulated plasma with which the veins of a lymphatic gland 

 were filled. The appearances found in these cases seem to depend on 

 the mode of preparation, which was essentially the same in them all. 

 The portions of gland or other mucus-containing tissue were immersed 

 in the hardening fluid as soon as they were removed from the body and 

 while they were still warm. The hardening fluid vvas either a ^ per cent, 

 solution of chromic acid, or the same solution mixed with an equal quan- 

 tity of methylated spirit. 



The preparations of the thyroid body are the best adapted to show the 

 whole series of coagulation-forms and the gradations between them. A 

 large number of the alveoli are filled with perfectly homogeneous or 

 jelly-like coagulum, which has coloured purple with the logwood staining- 

 fluid. The edge of the coagulum is very often vesiculated in such a 

 manner that it seems to be attached to the wall of the alveolus by the 

 points of crescent-shaped indentations. The same dentate edge of the 

 coagulum is often seen within the veins in chromic-acid preparations. 

 The form of coagulation in the thyroid that comes nearest to the homo- 

 geneous is where a number of fine granules appear to be imbedded in 

 the jelly-like mucus ; this produces a cloudy or spawn-like effect. Side 

 by side wdth these alveoli occur others, in which the coagulum is nothing 

 but a closely packed mass of granules without connecting substance ; and 



* Gesammelte Abhandlungen, pp. 66, 67. 



t See the writer's paper on " Physiological Processes of the Mamma " in the Eeport 

 of the Medical Officer of the Privy Council for 1875. 



