THE ACTION OF SALTON SEA WATER ON VEGETABLE TISSUES. 73 



ANATOMICAL STUDIES OF THE SPECIMENS SUBMERGED ONE TO FIVE YEARS. 



Obviously it was important to learn definitely what changes, if any, had taken place 

 in the tissues of these woody plants during their term of submergence, as indicated in 

 Plates 13 and 14l. It was found that almost the entire cortex had been lost from all specimens 

 except those which emerged in 1907, after a single year's immersion. A detailed study of 

 the cell walls was necessary in order to answer a question which had arisen relative to the 

 possible procedure of petrifaction. In addition, to give opportunity for study of anatomical 

 structures, a series of sections were made in the transverse, tangential, and radial planes. 

 These were placed in various liquids in order to soften them for sectioning on a special 

 type of swinging microtome. Sterile water, unsterile water, and concentrated hydrofluoric 

 acid were used. It was impossible to secure sections thinner than 25 microns in any of the 

 specimens not freed from mineral contents by hydrofluoric acid. In the specimens that 

 were treated from one to three weeks in concentrated hydrofluoric acid and thoroughly 

 washed it was possible to section 5 to 10 microns. In all cases the sections prepared from 

 the water or hydrofluoric acid softened specimens were stained with a water solution of 

 safranin for 24 to 36 hours and counterstained with aniline blue for a few seconds. These 

 sections showed entire absence of epidermis, cortex, and phloem. The woody cylinder 

 was unchanged in the xylem, ray, and pith regions. These conditions were the same in 

 both Prosopis and Larrea. 



Microscopical measurements of the walls in the cells of the ray regions and pith and the 

 xylem were made in order to determine whether there were variations in the tissues of the 

 woods that had been submerged one, two, three, four, and five years. In no case was there 

 any difference in the same region of the same plant. The walls of the ray cells were 1.9 to 

 2.5 microns thick; those of the wood fiber cells were 5.7 to 6.6 microns, and those of the 

 tracheae were 5.5 to 9.5 microns for Prosopis glandulosa; for the same regions of Larrea they 

 were 1.4 to 2.3 microns, 0.9 to 4.8 microns, and 5.5 to 6.5 microns thick, respectively. 



Sections of the woods softened in water preparatory to cutting were carefully examined 

 for evidence of mineral deposition. In no case could crystals other than calcium oxalate 

 be found. These crystals were present in the same relative places in the sections of the 

 fresh woods and in similar quantities as they were in the dried woods that had been sub- 

 merged. In view of this situation, one was forced to conclude that petrifaction had not 

 been initiated in any of the woods submitted for study. 



Since the samples of wood that were sent from the Salton Sea represented the final 

 stages of the decomposition processes which had decorticated them it was thought best 

 to secure water from the Salton Sea and reproduce, so far as possible, what had taken 

 place in nature Avhen the samples forwarded underwent decortication. Eight 5-gallon 

 carboys of Salton Sea water were sent to Chicago, four of which were labeled (A), (B), (C), 

 and (D). Pieces of fresh Prosopis glandulosa were placed in (A), of fresh Prosopis pubescens 

 in (B), and of fresh Larrea tridentata in (C); and fresh specimens of all three woods were 

 placed in (D). These cultures were started on December 9, 1911. The tightly stoppered 

 carboys were maintained at a temperature of 22° C. After five days, there was a pro- 

 nounced odor of hydrogen sulphide when the stoppers were removed from the carboys. 

 A milky condition developed in all of the containers supplied with fresh woods. Carboy 

 (C), containing Larrea tridentata, soon showed a remarkable growth of white threads fes- 

 tooned just below the neck of the carboy. These proved to be growths of Beggiaioa, 

 which is semi-anaerobic. The threads were neither on the surface nor at the bottom of 

 the carboy, but in an intermediate position with reference to the oxygen supply (Plate 14m). 

 Later, white films formed on the surface of carboys (A), (B), and (D). A careful examina- 

 tion of these showed that they were composed of filaments of Beggiatoa and free sulphur 

 hberated by the Beggiatoa when they used the hydrogen sulphide for energy releasal in 



