1885.] Mr J. R. Green, Observations on Vegetable Proteids. 231 



The microchemical characteristics were so peculiar as to be quite 

 unique. Taking into consideration, however, some of these re- 

 actions (especially in the light of the results obtained with 

 Hofmann's blue and Szyszylowicz's corallin-soda) : the presence 

 of, and the gradual breaking down of, the sieve-tube starch grains 

 and the mucilaginous degeneration of the protoplasmic contents : 

 there seemed to be little doubt that the callus is in reality of the 

 nature of a starchy mucilage. Such a body would give all the 

 reactions of callus. The author then drew attention to the wide 

 occurrence of the callus in connection with living cells, and re- 

 marked that from his observations he was led to believe that a 

 callus may also occur on the pits of young tracheids, e.g. the root 

 of Sambucus and the stem of Phaseolus. 



(4) Observations on Vegetable Proteids. By J. R. Green, B.A. 



The investigation of which the paper was a summary was 

 undertaken first to determine the proteid constituents of the calx 

 of the Cow-tree of South America (Brosimum galactodendron) . 



To this calx the name of vegetable milk has been given ; it is 

 described as closely resembling cow's milk in appearance, but 

 having a slightly resinous odour. It contains two proteids, one 

 being of the nature of a true albumin, the other belonging to the 

 group of peptones. 



The former is soluble in water, coagulates at a temperature of 

 68° C, and gives a well-marked xanthoproteic reaction. 



The latter of the two is the body which formed the subject of a 

 communication to the Society at the end of the October Term, 1884. 



In the calx of the Balata tree {Mimusops globosa) a globulin 

 body occurs which is absent from Brosimum. It is marked by 

 the usual reactions of globulins, but presents some features of 

 interest in connection with the effect of heat upon it. Its coagu- 

 lating point varies with the reaction of the liquid in which it is 

 dissolved. In an acid liquid opalescence sets in at 75° — 80° C, 

 and as it cools a precipitate settles out. This is insoluble in nitric 

 acid, but dissolves to a large extent in ammonia. 



In an alkaline solution the coagulating point is 79° — 85° C, and 

 the resulting precipitate is soluble in nitric acid but not in alkalis. 



The proteid bodies in both these fluids were found to be partly 

 destroyed by the spirit which was mixed with the calx for pur- 

 poses of preservation. Hence it seemed well to examine some 

 fresh plants. Those selected were Manihot glaziovii, the common 

 lettuce, and the cabbage ; these being representatives of three 

 natural orders not closely allied to each other. 



In the manihot a globulin exists with well-marked characters. 

 It is precipitated from solution by a current of C0 2 or by satu- 



