SPECIAL METHODS. 233 



(III, p. 12 of separata), these mucus-globules give the follow- 



ing reactions : They are insoluble 



in alcohol and in ether, and are un- 



changed either by boiling in distilled 



water or by the addition of a \% solu- 



tion of soda (Na 3 CO 3 ). In .3$ hydro- 



tJiloric acid they swell up and become FIG. 57 .-i, living ceii of scyto- 



M i 1,1 i, nema\ 2, cell of Nostoc. after 



invisible, and the Same result IS pro- staining with acetic carmine. 



, , . ^ f . i f s, mucus-globules. After 



duced by a mixture of two volumes of 



concentrated sulphuric acid and three volumes of water; 

 while they swell even in a mixture of one volume of sul- 

 phuric acid and 100 volumes of water, but remain visible. 

 3-5$ caustic potash solution causes swelling of the mucus- 

 globules, but in a \% solution they are unchanged. In a 

 .solution of potassium ferrocyanide acidulated with acetic 

 acid they stand out sharply and take a vacuolar structure. 

 In Millon's reagent they remain colorless, and also in iodine- 

 glycerine or in chloroiodide of zinc. Iodine and potassium 

 iodide solution and the above-mentioned dilute sulphuric 

 acid cause, on the other hand, a deep brown coloring of the 

 mucus-globules. Acetic carmine colors them deep red, and 

 a deep stain is produced by alum-carmine and by Delafield's 

 haematoxylin, after treatment with alcohol. 



Their capacity for staining with haematoxylin has been 

 disputed by Biitschli (I, 17). According to his statements, 

 osin is especially useful for staining them. The mucus- 

 globules may be made visible, even in haematoxylin prepa- 

 rations, by subsequent staining with this agent. [Hierony- 

 mus (II) has studied bodies found in the cells of Cyanophycefe, 

 which he terms cyanophy cm-grains and regards as identical 

 with the mucus-globules of Schmitz. According to his 

 statements, the bodies studied by him agree in their reac- 

 tions with those above described, and he gives the following 

 additional facts concerning them : They give no proteid 

 reaction. They are quickly dissolved by nitric acid, by a 

 solution of salt, by eau de Javelle, chloral hydrate, and 

 caustic potash solution ; but are insoluble in an artificial 

 gastric juice, in carbon bisulphide, in acetic acid, and in a 



