Scale-Leaves of Lathrea squamaria. By W. H. Gilhurt. 739 



again divide and subdivide, their ultimate divisions being composed 

 of spiral cells only in a single series. These vascular twigs are 

 very numerous, and only separated from the epidermis and glands 

 of the chambers by a single layer of cells, their course being 

 parallel with that of the chamber- walls. 



Bearing in mind the conditions under which Lathrea lives, viz. 

 always buried beneath the surface of the ground, often somewhat 

 deeply, the question naturally suggested by an examination of these 

 structures is. What is their function? for it cannot be supposed 

 that organs so highly specialized should exist and yet serve no 

 imj)ortant purpose in the economy of the plant. 



If a tangential section of a leaf of a plant growing under normal 

 conditions be removed, it will be found that all the chambers are 

 filled with a fluid somewhat turbid in appearance and having a 

 most decided acid reaction; we may therefore conclude that at 

 least these glands serve the purpose of secretion, the fluid secreted 

 being discharged outwardly. That this takes place somewhat 

 abundantly may be inferred from the fact that in the bank from 

 which I have taken my material, and which is composed of a light 

 friable loam, the soil immediately surrounding the Lathrea was 

 saturated with moisture, while all beside could be crumbled apart 

 with the fingers. 



The probability that they possessed absorbing powers also sug- 

 gested itself, and a large number of experiments have been made to 

 determine it, adopting the methods employed by Mr. Darwin with 

 Utricularia, &c. 



Thus five tangential sections were cut from the same leaf. 

 They were cut as thick as could be well examined under a ^-inch 

 objective, so as to have as many glands under observation as possible. 

 The sections were first placed under thin covers in distilled water 

 and examined carefully, when all the glands were seen to present 

 their normal appearance. The distilled water was then withdrawn, 

 and under four of the covers a solution of carbonate of ammonia in 

 the proportion of 1 to 400 was run in, and under the other a 1 per 

 cent, solution of cane sugar. 



After two hours they were examined, and no change was visible ; 

 after three and a half hours a few of the pediceUate glands showed 

 decided contraction of the protoplasm and a slight increase of 

 granulation ; after twelve hours all these glands showed contraction 

 of their contents, more or less ; and in twenty-four hours, in all, the 

 protoplasm was greatly contracted and coarsely granular ; while the 

 section ,in the sugar solution had only a very few of the glands 

 slightly affected. The sessile surface glands and the cells of the 

 epidermis remained unaltered, save by the general darkening of 

 their contents which invariably takes ])lace when the plant is cither 

 placed in water or exposed to air. Itepcating these experiments 



3 c 2 



