240 



Dr. W. Ord. Experiments on the 



[June 19, 



Experiment 6. — If glycerin be mixed in about equal quantities with 

 the acetic acid and cholesterin while still on the slide, and if heat be 

 applied, after the covering glass is in place, till bubbles form rapidly, 

 the slide instantly examined is found covered with spheres, some as 

 large as fat cells and quite regular, others egg-shaped, and others 

 aggregated into masses (fig. 12). The ma3ses are dense and very 

 brilliant. As cooling proceeds all the spheres break up. The large 

 ones contract at their surface, and seem thereby to squeeze out fluid 

 from the interior, which takes at first the form of tubes, afterwards of 

 spheres. An active movement of this kind often results in the forma- 

 tion of a group of small spherules in the place of the large one, looking 

 like a glomerulus of spores (figs. 13, 14), Presently these in turn change 

 each instantaneously into needles, the change proceeding as follows : — 

 a single spherule darts away from the mass ; as it goes it leaves a stiff 

 raphis in its course, and it is itself proportionately diminished in size, 

 till its last fragment forms the point of the raphis (figs. 15, 16). The 

 ball is, so to speak, unwound into a stiff thread of glassy substance. 

 Here and there spheres break up, without change of place, into 

 variously shaped tufts of needles. 



'Experiment 7. — Acetic acid is added to cholesterin and albumen, 

 and the mixture is heated to boiling. Examined now as quickly as 

 possible the mixture presents spheres and tufts of needles rapidly 

 growing in the fluid part of the field; spheres and spheroids and 

 combinations of most fantastic shapes in the transparent albumen. 

 The spheres are at first perfectly homogeneous and circular in outline 

 (figs. 17 — 26). After a time they become oval and gradually a little 

 pointed at the ends. Then usually a little globular protrusion forms at 

 one end or both ; then a zone of indentation is drawn round the oval, 

 usually at about one-third of the length of the surface from the pro- 

 trusion ; the interior next gives indication of a subdivision of the 

 substance of the ovoid into two, three, or four mutually compressed 

 spheroids ; and at last the whole changes, with magical suddenness, 

 into a crystalline mass of obscurely rhombohedral shape. In process 

 of time this mass breaks up yet further into raphides. The great 

 transformation is attended by upheavals and depressions of the sur- 

 face, causing a general appearance of singularly life-like convulsions 

 and contortions of the mass. All the change is most rapid during 

 cooling, but it continues slowly for hours and days subsequently till 

 every particle of cholesterin has come to the needle form. If solutions 

 of gelatin be used instead of albumen, similar results are observed. 

 In the gelatin spheres are readily formed, and slowly turn into needles. 

 If acetic acid be added and heat applied the rapid conversion of 

 spheres into needles, attended by active convulsive movements, can be 

 conveniently watched in the cooling mixture ; and if glycerin be used 

 as well a great variety of lively transformations may be witnessed. 



