THE ACTION OF 8ALTON SEA WATER ON VEGETABLE TISSUES. 76 



It is not understood that these analyses represent the chemical conditions of cultures, 

 in which the various woods were placed, during the entire time of the investigation, inasmuch 

 as the chemical changes were taking place constantly due to the bacterial organisms which 

 were reducing the sulphates and the organisms which oxidized the sulphureted hydrogen. 

 It is (luite certain, therefore, that chemical analyses taken at other periods would have 

 shown a different relationship existing in the quantities of sulphates contained in the 

 cultures of these various woods. For instance, in the culture of Larrea trideniata the 

 evidence of the evolution of hydrogen sulphide preceded that in the other culture. An 

 analysis gotten at the time the supply of hydrogen sulphide was especially abundant in 

 the Larrea culture would certainly have given somewhat different results from those indi- 

 cated in the above table for Larrea tridentata. 



Chemical evidence shows that whenever an appreciable quantity of hydrogen sul- 

 phide is present in water whose sulphates have been acted upon by bacterial organisms, 

 the reduction of sulphates has taken place and the decrease in the amount of sulphates 

 is approximately proportional to the increase of the hydrogen sulphide. 



Since the Beggiatoa lays hold of the hydrogen sulphide for energy releasal and oxi- 

 dizes the sulphide, giving rise to acids, the question arises, might not any break-down of 

 woody tissue present in a culture where this process was going forward be due to the pres- 

 ence of newly formed acids? This question was disposed of by the fact that the quantity 

 of acids is very small and is immediately cared for by bases present in the water. Therefore, 

 interesting as are these chemical changes, due to the reduction action of Spirillum desul- 

 phuricans and the oxidizing action of Beggialoa, they can not be held to explain the de- 

 corticating changes observed in the wood sections placed in cultures of Salton Sea water. 



DECORTICATING PROCESSES IN SPECIMENS OF FRESH WOOD IMMERSED 



IN SALTON SEA WATER. 



If the substances in the water of the Salton Sea, either before or subsequent to the 

 processes carried on by the organisms above mentioned, were not active in producing 

 decortication, there is only one possible avenue of investigation open in search for the 

 causal factors of cortex removal. 



Certain enzyme-producing bacteria would in all probability have access to the tissues 

 which were decomposed. Investigations with reference to these forms were instituted 

 in two directions; first, a series of controlled cultures were prepared consisting of three 

 sets: A, a series of sections from Larrea tridentata, Prosopis glandulosa, and Prosopis 

 pubescens were sterilized and placed in cultures of unsterilized Salton Sea water; B, sec- 

 tions of the same woods unsterilized were placed in cultures of sterilized water; C, sections 

 of the same woods were sterilized and placed in cultures of sterilized Salton Sea water. 

 These cultures were kept at room temperature and series A and B soon gave evidences of 

 bacterial activity. The changes in B series were considerably greater than those in A, 

 while series C remained inactive. Throughout the whole test it was noted in the sections 

 from series A and B, after three weeks of culture, that the cortex and phloem loosened 

 and slipped from the woody cylinder with ease. 



In addition to the controlled cultures, sections of fresh Prosopis glandulosa were made 

 in transverse, longitudinal, and tangential sections and placed in a 5-gaIlon carboy. Also 

 specimens of branches 15 to 25 c.c. long were immersed in the same gross cultiu-e. Some 

 of these branches were paraffined at the end, so that no bacterial organisms could secure 

 a portal of entry to the cortex except through a superficial break in the epidermis. Other 

 specimens were broken in such a way as to leave a ragged and exposed surface at the ends, 

 giving the most ready access to the cortex, phloem, and cambium. Similarly 5-gallon car- 

 boy cultures were made of Prosopis pubescens and Larrea tridentata. These gross cultures 

 kept under observation for six months gave distinct results with reference to decortication 



