142 Mr. C. Creigliton on Coagulation-appearances [June 15^ 



these granules vary much in size in different alveoli. In some the co- 

 agulated mucus becomes finely divided, while in others it is broken up 

 into only a few rounded masses of relatively large size. Perhaps the 

 commonest size of the globules or granules of mucus is about one third 

 the diameter of the red blood-corpuscle, while the largest masses may 

 be twice its diameter. All the other coagulation effects can be shown to 

 be modifications of the granular condition; they range from not very 

 complex groups of granules or spherules to a close meshwork, and to 

 long branching filaments like the threads of ordinary fibrin. Many 

 alveoli of the thyroid body show the simpler reticular arrangements of 

 the coagulated mucus ; the more complex reticular appearances are best 

 seen in two preparations of the mammary gland ^^ith mucus in the 

 ducts ; and the filamentous appearance is best seen in the large colloid 

 collections that occur throughout the two myxomatous tumours. The 

 mucus in the mammary ducts has the following singular appearance : — 

 Along both sides of the duct there is a strip of homogeneous mucus which 

 adheres to the wall by means of the dentate points already mentioned ; 

 further towards the centre of the duct the mucus is broken up into a 

 mass of granules ; and the broad central space is occupied by a network, 

 the meshes of which become larger towards the middle. The appearance 

 looks as if it had been produced by a shrinking of the mucus towards the 

 sides of the duct. The fibres of this reticulum are short and thick, and 

 there arise from them numerous knob-like projections, chiefly at the 

 points where the fibres seem to branch ; and where the fibres seem in the 

 section to end, their free extremities are found to be capped with the 

 same knob-like enlargements. These round processes are of the same 

 diameter as the threads or cords on which they are seated. The substance 

 of the whole reticulum is uniform, and is coloured throughout with the 

 staining-fluid. 



The plan of this singular arrangement becomes clear by studying the 

 simpler forms of it, as seen in the alveoli of the thyroid body. Several 

 granules or spherules of mucus are found to have arranged themselves like 

 a group of crystals. Eound a central spherule three or four others (as it 

 appears in the section) are regularly grouped to form a small rosette. 

 When several of these rosettes are placed in apposition, the optical effect 

 is that of branching cords or fibres with knob-like projections arising 

 from them at short and equal intervals. The appearance of a nodulated 

 fibre is best seen where the elements composing it are small. The smaller 

 the granules or spherules are, the longer do the intervals seem between 

 the upright knob-like projections ; but if the focus is altered, there come 

 iato yiew other projections arising along the course of the apparent fibre 

 at other angles or in other planes. 



The common starting-point of the various coagulation-forms that have 

 been described appears to be that, under the influence of certain re- 

 agents, the warm albuminoid fluid is deposited in the form of larger or 



