1886.1 



Proteid Substances in Latex. 



29 



directed to the seed. ~No doubt special facilities for investigation are 

 afforded thereby, for the different bodies can be detected there by the 

 aid of the microscope, and their behaviour under the action of 

 different reagents watched. Hence valuable results have been 

 arrived at, and our knowledge of vegetable metabolism has made 

 considerable advance. By the investigations of Hoppe-Seyler,* Weyl,f 

 and Zoller,J the similarity of vegetable proteids to those occurring in 

 animals was pointed out, members of the globulin family at least 

 being shown to exist. Later Vines, by an exhaustive examination, 

 both macroscopic and microscopic, of a very large number of seeds, 

 has added greatly to our knowledge of these bodies, proving that 

 besides globulins, a form of albumose, albuminates, and coagulated 

 proteids are to be isolated, and showing the actual conditions and 

 proportions in which these are present in the seeds. § 



It is evident, however, that our knowledge of the seed, even if made 

 complete, will not give us all the information we require concerning 

 the nitrogenous metabolism of the plant. The condition of the 

 proteid matter at a time antecedent to its appearance as reserve 

 material must be considered as equal in importance and in interest. 

 The round of changes going on normally in the leaves and the soft 

 tissues of the stem has hitherto remained unknown, nor had we any 

 knowledge of the condition and characters of the proteid bodies circu- 

 lating in the plant, and met with in the latex and in the soft green 

 parts until recently, when Martin || published an account of his in- 

 vestigations into the nature and action of the ferment present in the 

 Papaw plant (Garica papaya) and has therein described certain pro- 

 teids which he has found to be present in the dried milk of the fruit 

 of the plant. These he says are four in number, two belonging to the 

 group of the albumoses, a globulin and an albumin. To the albumoses, 

 which are the most plentiful in amount, he gives the names of 

 a. and ft phytalbumose. 



During the summer of 1884 I was enabled, through the kindness of 

 Mr. Thiselton Dyer, Assistant Director of the Royal Gardens, Kew, 

 to make some investigations into the composition of the latex of 

 several caoutchouc-yielding plants belonging to the natural orders 

 Apocynece and Sapotacece.% In most cases the latex was a very com- 

 plex fluid, containing, besides proteids and carbohydrates, considerable 



* " Med.-Ckem. Unters.," 1867. 



f " Zeitsclir. £. Physiol.-Chem.," i, 1877 ; " Ber. d. deut. Ckem. Ges.," xiii, 4, 1880. 



X "Ber. d. dent. Chem. Ges.," xiii, 10, 1880. 



§ "Journal of Physiology," vol. iii, No. 2. 



|| Ibid., vol. v, No. 4, and vol. vi, No. 6, p. 336. 



% [These samples, thirty-four in number, were collected for Dr. Tines -with ycvy 

 great pains and trouble by Mr. D. F. A. Hervey, Eesident Councillor, Malacca. — 

 W. T. T. D.] 



