THE BEHAVIOR OF CERTAIN MICRO-ORGANISMS IN BRINE. 69 



The fluctuations shown by determinations of specific gravity and by census of the 

 organisms in brines collected at the salt works are confirmed by the behavior of the brine 

 algsB in cultures in sterilized brines and on such brines solidified by the addition of 1 per 

 cent or less of agar-agar. In liquids, indoors and out, the algae do not generally form 

 colonies, but on agar-agar brine they commonly do so, especially when cell-division is 

 stimulated by dilution of the brine or by transferring the algae from a higher to a lower 

 concentration. Even slight decrease in density results in decided increase in the rate of 

 cell-division, whether upon a solid medium or in a liquid. 



Concentration of the brine, on the other hand, carried far enough, induces the oppo- 

 site effect, permanence of the cells instead of their division. When salt is crystallizing 

 out the alga) begin to encyst. Although I have never seen all the cells go over into the 

 resting condition, the number so doing increases with the concentration. This change 

 takes place only slowly, so far as my observation goes. 



The germination of encysted cells takes place when the brine in which they lie is 

 diluted. The germination of a resting cell consists in its division into many small cells, 

 gametes or zoospores. These presently escape through the broken or digested wall of the 

 mother-cell. The addition of water, then, favors both vegetative cell-division and this 

 reproductive cell-division, both of which, since these algae are unicellular, result in increas- 

 ing the number of individuals. 



Whether the cells thus formed in the germination of a resting spore are gametes or 

 zoospores I can not say; for I have never seen conjugation take place. Cells in certain 

 stages in division might so closely resemble cells in certain stages of conjugation that they 

 would be indistinguishable, unless the processes were seen at their beginnings. 



The color of the concentrated brines in the salterns of the Bay of San Francisco is 

 due to a small chromogenic bacillus, 3.2 to 3.3/i wide by 3.4 to 3.6m long, which not only 

 lives in saturated brines but also upon and in the heaps of salt as it is piled for drainage 

 and shipment. Small volumes of brine and small masses of salt, as they may be kept in 

 glass vessels in the laboratory, owe their pink hue to this organism. Color will develop 

 in sterilized colorless brine of suitable concentration if inoculated from a pure culture or 

 other source of this organism. On agar-agar it grows either as distinct colonies of deep-red 

 hue or more diffusely over a moister surface. In either case, the pigment diffuses beyond 

 the outlines of the colonies into the brine or agar-agar. 



Experiment proves that this organism, inoculated with unsterilized salt into salt 

 cod-fish, will cause the cod-fish to turn red, thus making it unsalable; and that the cases 

 of cod-fish reddening in the grocery or in the larder are due to the growth of this bacillus 

 on the fish when the fish is kept in an unduly moist and cool place. Since all the brine 

 organisms are killed by moderately low heat, sterilization of the salt is simple. Thus, 

 sterilized salt is a remarkable preservative; but unsterilized salt often carries organisms 

 the putrefactive or other destructive activities of which it can not check. 



Quantitative analyses show that, in the course of salt manufacture, the qualitative 

 changes in the brine are as great as the quantitative, that the proportions of calcium and 

 magnesium change greatly with relation to each other, that calcium becomes very much 

 reduced by precipitation in the "pickle ponds" and elsewhere, while the solution becomes 

 richer and richer in magnesium and potassium as it concentrates. The osmotic, adsorp- 

 tive, and other relations of the brine organisms to their environment are so extraordinary 

 that they may well be studied for the light they may throw on the more usual adjustments 

 with which we are more familiar, but of which, in fact, we are almost equally ignorant. 



In these extraordinary organisms, low though they are according to schemes of classifica- 

 tion, simple though they are in form, we have a remarkable illustration of the adaptabiUty, 

 the plasticity, of living things. In the living organism, a creature of substance and of circum- 

 stance, we see behavior molded by circumstance, substance changing to meet conditions. 



