( 170 ) 



It is xerv pofiiliar lluil finely divided iioii-vohilile acids, e. <;•. 

 stearic' acid, render the lipase already inactive in a cnltnre liquid. 

 If thus we add finely dixided stearic acid to a boiled fluorescens 

 liquefaciëns culture it splits no more fat. When we now filtrate the 

 fatty acid, the filtrate contains very little or no lipase, but it is 

 bound to the. fatty acid on the filter and can again become active 

 l)y neutralisation of tlie acid. 



Lil)ase can thus be almost (piantitatiNely renu)ved from a licpiid 

 by means of finely divided fatty acid. 



The lipase is not, however, bound U) the fatty acid if the litpiid 

 which contains it reacts feebly acid. If then the fatty ^xcid is filtrated 

 off, the tilli-ate contains I he li|)ase. which after neulrulisalion of the 

 former auain becomes active. 



From this investigation follows that the group of the melting 

 fluorcscents secrete a fat-splitting enzyme wlii(di tolerates heating 

 from 99° — 100° C. for 5 minutes, or a minute's boiling without 

 being perceptibly decomposed. This enzyme is called fheruw-toh^miit 

 lipase. 



It is bv this property distinginshed from the enzymes known lill 

 now and likewise from the lipase formed by the group of JJ. lijio- 

 I title Kill, Jl. stutzcri, Ji- jluorcsceiia non liqiiefacii'ns, and from that 

 of the moulds : Oidium laclls, Penlcllliuni cjlaucwn, A.spfiyilhis ni(/er 

 and Cladoaporium hutyri. 



The properties of the lipase of the latter micro-organisms and those 

 of the thermo-tolerant lipase exhibit for the rest a great similarity 

 as is shown by the way of diffusion through agar and gelatin media, 

 and by the behaviour of both enzymes towards soluble acids and 

 non-volatile fatty acids. 



Chemistry. — ''On retro^/resstre meltbuj- point lines." (Second Com- 

 munication) By Prof. A. S.mits. (Communicated by Prof. J. D. 

 VAN DER Waals.) 



(Goramuuicated in the meeting of May :27, 1911). 



Introduction. 



In my first paper on this subject ^) 1 started the discussion of 

 retrogressive melting-point lines in the system H^O — Na._,S04, which 

 discussion will now be completed, and improved iti a single point. 



To reach a stricter accuracy in my reasoning I will now derive 



1) These Proc. Sept. (lV)U9j p. 227, 



