211 



Table 13. The preaoice of a lipase i)t the iissiie of Sj>o)if/illit. 

 In order to prove tliis presence I first made a sufficiënt quantitv 

 of pure emulsion of fat (oildrops) from the sponge tissue, in ti)e 



following way: 



A living Spongilla (green or colourless; or geramulae) is rubbed and 

 pressed, the parts of the skeleton removed; then tlie pressed out 

 hquid is centrifuged for about 5 minutes, by which a tliick niass (of 

 sponge cells and chhjro})liYll corpuscles) sinks to the bottom and the 

 Hquid remains. Tlie kitter contains numerous oildrops (and, niay be, 

 chlorophyll corpuscles). Next this liquid is evaporated at 60°; tlie 

 residue extracted by etlier; the ether then fdtered and evaporated 

 too. Then )-emains a substance of vaseline-like consistence, sticky, 

 with a strong sniell, nielting when warm and then forrning a lasting 

 greasy spot on paper, indissolu1)le in water, but dissoluble in ether 

 and xylol, stained red witli sudan III and black with osmic acid. 

 Consequently this substance is fat. By boiling in water it becomes 

 an emulsion again, containing the same oildrops we originally i)ro- 

 ceeded from. (Besides, tliis boiling is necessary to destroy all traces of 

 enzymes, that might still be present.) I shall call this boiled liquid 

 ,, emulsion". 



Next another living sponge is rubbed and pressed, etc, etc. (see 

 above); while the liquid, i'emaining after centrifuging, is kept. This 

 will contain the lipase, at least when it is present in sponge tissue. 

 This li(iuid I shall call „enzynie". 



As one knows, tlie lipase splits the lat by hydrolysis into its com- 

 ponent parts: the glycerine and the acids. It is the arising of the 

 latter we have to sliow in our experiments; in the following way: 

 A certain quantity of ,,enzyme" and „emulsion" are mixed; to this 

 we add one drop of the indicator phenolphthaleine — being red in 

 alkaline milieu, but colourless in an acid one — and such a small 

 quantity of an (alkaline) Na^ CO3 solution that the whole mixture 

 becomes light-red. The acids, then, set free from the „emulsion" by 

 the lipase will make the red colour disappear. In order to get a pure 

 result it is necessary, however, that in this mixture no acids arise in 

 another way than by the hydrolysis due to the lipase; or at least 

 that we reckon with it, if it proves to be the case. 



3 Series of experiments (I, II and III) were made at the same time, 

 in which the following substances were mixed: 



I. 15 drops of „enzyme" + '2.5 cM* of „emulsion" +1 drop of phenolph. + Na^ CO3 sol. 

 II. 15 drops of „enzyme" -f 2.5 cW of water + 1 drop of phenolph. + Na^ CO3 sol. 



ÜI. 15 drops of water + 2.5 cM-' of „emulsion" + '1 drop of phenolph. -{- Naj CO3 sol. 



