54 THE SALTON SEA. 



taking up water, the evidence of incomplete preservation will become the more pronounced 

 the more moderate the temperature. Of these bacteria one is chromogenic, and is the 

 organism which causes salt fish to turn red, a result which makes it unsalable. Presumably, 

 the putrefaction accomplished by this red chromogenic organism is no more undesirable 

 in what is used as human food than those putrefactions unaccompanied by pigment forma- 

 tion; but in this instance a handsome color seems to be more offensive than an unmistak- 

 able odor of decay. The same peculiar psychological phenomenon is to be noted in the 

 public taste regarding milk : red milk is unsalable, while the various forms of spoiled milk 

 have a pronounced market value. This chromogenic organism living in concentrated 

 brines and upon damp salt is the cause of the color of the salterns on the shores of the Bay 

 of San Francisco. It is also of economic importance, since it sometimes makes a certain 

 article of food unsalable. The cultural and other characteristics of this organism will be 

 described later. 



Perhaps still more surprising than the occurrence of alga? and bacteria in brines so 

 concentrated that salt is crystallizing out, is the growth of the two species of Dunaliella 

 and of the red and other bacteria on the great heaps in which the salt is piled near the 

 salterns for shipment elsewhere. The salt, crystallizing out both on the bottom of the 

 brine ponds (or salterns) and on the upper surface of the brine, accumulates on the bottom, 

 often in very regular layers. The salt may form crusts on the surface. These, breaking 

 under wind and wave action, founder as flakes of greater or less size which lie more or 

 less regularly piled on the bottom. Between these flakes all sorts of floating objects may 

 be caught, animate as well as inert, there to remain until the salt is completely disinte- 

 grated once more by solution. From the bottom of the salterns the salt is removed in 

 barrows and piled in great heaps, say 20 feet wide, 40 feet long, and 12 to 15 feet high, 

 with sloping sides and ends. From these heaps the mother-liquor drains off, leaving ani- 

 mals and plants alike stranded in the mass of salt. Ordinarily the heap glazes over as a 

 result of the first rain and subsequent fair weather, and the salt is visible for a long distance 

 on the flat shore as a white and sometimes shining pyramid. Examination of the salt, 

 however, will generally disclose the presence of green or brown or red material on and in 

 the mass of white or soiled crystals. The green and brown material commonly occurs in 

 layers, and wherever there is sufficient moisture and light there is evidence that the cells 

 are active. The colorless bacteria are everywhere throughout the mass, but when the 

 chromogenic ones occur at all abundantly, as they do when there is ample moisture and 

 no excess of light, it is as pink patches of soft and gelatinous consistency, on the surface 

 or throughout the mass of salt. These plants, algae and bacteria, respectively, were so 

 abundant during the winter of 1910-11, which was distinguished by unusually heavy 

 seasonal rainfall, as to give the salt a greenish or pink tinge wherever they occurred. They 

 were correspondingly inconspicuous in the winter of 1911-12, during which there was only 

 a scanty seasonal rainfall. The connection between these organisms and the changes in 

 their environment will become plainer, however, from the records (see pp. 56-60). 



RECORDS. 



My first observations were made in the autumn of 1906, at the end, therefore, of the 

 long dry season. Thus, on October 25 I found the water in the salterns red in color, of a 

 shade between that of blood and of iron-rust, with salt crystallizing out on the surface 

 and edges of some of the ponds, the crystals drifting as floating flakes before the wind and 

 accumulating m the corners to leeward like an "ice-pack." The density of the water 

 determined by hydrometer indicating specific gravities from 1.000 to 1.500, ranged in dif- 

 ferent salterns from 1.050 to 1.225. This densest brine was almost sirupy in consistency 

 and all of them filtered very slowly, the papers rapidly clogging with salt crystals and other 

 solid matter. Examined in the laboratory on the following day, the brines were found 



