Then shall our marble palaces become us, and the pure, invigorating breezes from the Golden Gate, heartened and glorified by the golden sunshine, will be the symbol of the spirit of this university State of ours, and of this, our State University.

LIFE IN HOT WATERS.*

By W. A. SETCHELL.

We know that all ordinary living things, whether plants or animals, whether higher or lower in the scale of organization, are soon killed when subjected to a temperature raised appreciably above that at which they are accustomed to carry on their vital functions. We know that an Amoeba, for example, is killed almost instantly by a temperature of 40 degrees C. (104 degrees F.), and cannot endure for any considerable period a sustained temperature several degrees lower. We know that even the raising of the temperature of the waters of a small shallow pool exercises an injurious and often fatal effect upon the life within it. Consequently, we are more or less surprised to find that, in certain hot waters, life is said to exist near to or even up to the boiling point.

The existence of organisms in hot springs at a temperature near the boiling point was especially asserted in connection with the arguments against spontaneous generation. The advocates for spontaneous generation claimed that by boiling a solution vigorously for several minutes and then sealing it up hermetically, two desired conditions of the experiment were obtained; in the first place, it was assumed that all the organisms present had been killed by the boiling, and in the second place, all entrance of germs from without had been effectually prevented by the manner

* Abstract of an address by the President of the Science Association, May 3, 1898.

of sealing the vessel. Since the second claim was sound enough, and since, even in the most hermetically sealed flasks, organisms did appear after awhile, the opponents of the doctrine of spontaneous generation attacked most vigorously the first assumption. But it was necessary for them to demonstrate that there were organisms not killed by boiling. In the first instance, this brought the attention of the opponents of the theory to the inhabitants of the hot springs, and observations were published showing that organisms do live in waters of a temperature much higher than the ordinary. In this way, the life of the hot springs and other hot waters became a matter of scientific interest, rather than one of mere curiosity. Of course, we know now that the opponents of the doctrine of spontaneous generation found other much more forcible and convincing arguments than this one, and were able, through Cohn's discovery of the Hay Bacillus, to explain the appearance of organisms in these boiled and sealed infusions. But there came into existence at that time, a series of statements as to the existence of life at higher temperatures, which are of extreme interest, but which need to be subjected to a critical examination as to their accuracy and significance.

We find existing outside of the laboratories two sets of hot waters, those of the hot springs and those which we may call artificial hot waters. The latter are the waste waters from boilers, etc., and are usually temporary, or at least, intermittent. They do not enter to any great extent into our consideration, but usually, if they are sent forth continuously for any length of time, certain organisms will be found in them, and these will also be found to be species absolutely distinct from any found in the ordinary colder waters.

The hot springs or natural hot waters, on the other hand, are found all over the world, especially in mountainous regions, yet are sufficiently local to be objects of considerable curiosity and interest. Many of these hot springs have become the attractive features of watering-places, such

as those at Karlsbad in Bohemia, those at Baden-Baden, the Julian and Euganean Springs in Italy, the Hot Springs in Arkansas, the Geysers of the Yellowstone Region, and numerous hot springs throughout California.

The Geysers of Iceland, those of the Yellowstone, the various hot springs in New Zealand, as well as many others, are of extreme interest and importance to the geologist on account of the formations, both siliceous and calcareous, which are produced from their waters. It has been demonstrated, moreover, in connection with both the deposits of travertine and also those of siliceous sinter, laid down in connection with the hot springs, that they are produced through the agency of living organisms in the springs. The existence of living organisms in the waters of higher temperatures, therefore, has an additional interest in this connection.

In connection with any investigation of the organisms of the hot waters, we must necessarily ask the following questions: What sort of organisms are they? At what temperatures do they flourish? How high a temperature can they endure? Have they any special organization which enables them to endure these high temperatures and yet flourish? Do they prefer the higher temperatures? How has it all come about?

Before answering these various inquiries, it may be well, perhaps, to note very briefly what has been written upon the subject. The algae of the Karlsbad Springs received the earliest attention. Bishop Agardh, of Lund in Sweden, described the species occurring there, in 1827. These descriptions were amplified and corrected by others, until finally in 1863, Ferdinand Cohn gave the most complete account of them, and called attention to the part played by them in causing the deposition of lime from the waters. The algæ from the springs of Italy were described by Meneghini, those from the Yellowstone by Weed and Tilden.

From these various accounts we may obtain certain fairly definite ideas as to the character of the life of these

waters, together with some information as to the temperatures at which the different organisms grow. My own investigations, carried on in the hot springs near San Bernardino, supplement and emend these in several particulars.

From all accounts and from my own observations, I think that we may safely say that there are no animals living in the hotter waters, that is to say, in waters of a temperature many degrees over 40 degrees C. (or over 100 degrees F.). Of the algae, all the forms living in waters over 40 degrees C. belong to one group, that of the Cyanophyceæ or Blue-Green Algae. Although certain other species are credited in one or two cases as living at decidedly higher temperatures, yet there are, in my own mind, very good reasons for seriously questioning the accuracy of these statements. My own observations at the Arrowhead Springs near San Bernardino, as well as at the Waterman and the Harlem Hot Springs near the same place, lead me to question the existence of any organisms other than the BlueGreen Algæ in waters over 43 degrees C. I may say a word here, in explanation, as to how my own records of temperature were made. At the Arrowhead Springs the waters issue at a temperature of 90 degrees C., and flow down a stony bed in the cañon, in a stream at first small, but soon increased from small side-streams flowing into it from various other hot springs along the sides of the cañon, until finally it becomes a stream of considerable size. The algæ occur in this stream, both submerged in the central portion and partially exposed to the air in the water along the edges. The temperatures taken were those of the alga submerged anywhere from one inch to a foot, in midstream, for it was found that, at the edges, the temperatures of the tufts of algae were decidedly lower. Moreover, the bulb of the thermometer was placed directly in or against a particular tuft. In this way the temperatures at which the algæ were growing were obtained as accurately as possible. I emphasize this because it is very difficult to obtain accurate