CHAP, ix.] SIEGFRIED'S RESEARCHES ON RETICULIX. 403 



water for a period of only 20 minutes it splits up, with the formation 

 of a powdery, phosphorus-containing proteid, reticulin, a small 

 quantity of gelatin being formed 'at the same time. Reticular tissue 

 thus appears to be formed, either of a microscopically undistinguish- 

 able mixture of reticulin and collagen (a view which, in addition to 

 its inherent improbability, is disproved by the fact that collagen does 

 not, like reticular tissue, yield gelatin when merely boiled for 

 20 minutes), or of a substance which when boiled with water splits 

 up into reticulin and gelatin. It is thus as different from white 

 fibrous tissue as it is from elastin. 



Reticulin. 



Preparation The mucous membrane of the pig's intestine is 

 of purified re- employed for the preparation of pure reticular tissue, 

 tiform tissue i n preference to that of other animals, because of its 



rom the intes- com p ara tive freedom from yellow elastic and white 

 tinal mucous ni .. J . ,, , 



membrane. fibrous tissue. A separation of the mucous membrane 



from the submucosa is very readily effected. The raw 

 mucous membrane (Siegfried employed each time that obtained from 

 the intestines of from 8 to 17 pigs) is broken up and washed in large 

 quantities of water, during which process any accidentally adhering 

 fragments of submucous tissue are further separated. Then it is 

 digested at a temperature of 37 C. with a solution of trypsin con- 

 taining NaHCO 3 and Na^O, 1 , thymol or chloroform being employed 

 to prevent decomposition. By this process of digestion, the lymphoid 

 cells are got rid of, their protoplasm being dissolved, whilst their 

 nuclei are partly dissolved by the alkaline solution and partly remain 

 suspended in it. At the end of forty-eight hours, the tissue which 

 has been subjected to this process is poured into open vessels and is 

 stirred and kneaded with large quantities of water which are fre- 

 quently renewed. In order to separate it from water, without contami- 

 nation with accidental impurities, the tissue is centrifugalised and 

 then repeatedly treated with alcohol and again centrifugalised. The 

 tissue, which has been thus freed from water, is placed in large 

 *Soxhlet fat-extracting apparatuses and digested with ether for 

 several days. Having been thus freed from fat, it is again digested 

 during a period of 48 hours with a more concentrated trypsin 

 solution than was employed the first time. The washing with 

 water, alcohol, and ether is repeated as before, when the reticular 

 tissue is obtained in strands of a light-grey colour, which swell up 

 in water, forming delicate porous membranes possessing the structure 

 of the original mucous membrane. When examined microscopically, 

 these membranes appear to be composed of pure reticular tissue, free 

 from the white fibres of connective tissue and from lymph cells. 



1 Siegfried employed 25 to 30 grms. of the so-called (very active) pancreatin made 

 by Parke, Davis and Co. of Detroit, U.S.A., 50 grms. of NaHC0 3 , some Na 2 C0 3 and 

 40 litres of water. 



262 



