44 
MR. J. R. GREEN ON THE CHANGES IN THE PROTEIDS 
%vas first given to tlie reaction of the germinating seed. This was found to be faintlv 
acid, and consequently a fluid containing free HC1 to the amount of '2 per cent, was 
used. Further experiments bearing on this point will be detailed later. It was, 
unfortunately, not possible to reproduce the conditions obtaining in the seed, where 
the proteid matter is in considerable excess and but little fluid is present. 
Some fibrin was taken and boiled for twenty minutes in weak HC1, to destroy any 
possible ferment adherent to it. It became swollen up and of the usual semi-trans¬ 
parent appearance. A quantity was put into a dialyser with about 30 c.c. of the 
dialysed glycerine extract, which was mixed with an equal bulk of ‘4 per cent. HC1; 
and the dialyser was immersed in a beaker containing 100 c.c. of ‘2 per cent. HO. A 
control was kept by having a precisely similar quantity of the glycerine extract boiled 
before adding the fibrin, and another by putting a similar quantity of fibrin into '2 per 
cent. HO alone. All were then placed on a water bath at 37-40° O, and left to 
digest. After a period of time, varying in different experiments, but in every case 
very much more prolonged than is necessary with gastric or pancreatic extracts, the 
dialysate from the tube which contained the unboiled extract of the seeds was found 
to contain peptone, as evinced by the pink colour given on addition to it of excess 
of NaHO and a drop of CuSO^,. When this had been well marked for some time, 
the dialysate was boiled. No turbidity resulted, nor did any opalescence or pre¬ 
cipitate appear on neutralisation. Alcohol gave a precipitate which settled out slowly. 
On concentrating the dialysate, and evaporating slowly, crystals were formed which 
were recognisable under the microscope as those of leucin. They were carefully com¬ 
pared with the crystals of leucin figured by Funke in his ‘ Physiological Atlas,’ and 
corresponded entirely with them.* When the liquid containing these was evaporated 
to dryness with HN0 3 , and the residue treated with caustic soda, and again 
evaporated, it gave the oily drop said to be characteristic of leucin (Scherer’s test). 
Besides these, others were present in less quantity, which, from their form, appeared 
to be those of tyrosin. The liquid containing them changed to a pale pink colour 
when boiled with Millon’s reagent. This was confirmatory of the presence of the 
latter body, though it cannot be held to be by itself conclusive, as a trace of peptone 
present, if not enough to be precipitated by the Millon’s reagent, would give a 
somewhat similar reaction. 
No digestion took place in either of the control tubes. 
The process was continued in this case for six days. In another experiment I 
worked with an extract that had not been dialysed, when I proceeded rather 
differently. In the dialyser I put 30 c.c. of the extract and 30 c.c. of - 4 per cent. 
HC1. In the beaker in which the dialyser was immersed I put 120 c.c. of '2 per cent. 
HC1. After 24 hours I poured this away and substituted 120 c.c. of fresh HC1 
•2 per cent. I changed this again after 24 hours more, and again after a further 
* The microscopic slides of these crystals were farther examined for me by Dr. Sheridax Lea, who 
kindly allows me to quote Iris opinion that they were those of leucin. 
