June 12, 1903.] 



SCIENCE. 



935 



yidual references have been made to the 

 organisms living at higher temperatures in 

 siLch springs, such as are tabulated by 

 Davenport in his ' Experimental Morphol- 

 ogy ' (Vol. I., pp. 249-267), under the 

 heading of ' Acclimatization to Heat.' As 

 may be seen from the references there 

 given, and more partieiilarly from Daven- 

 port's notes on the different records, as 

 well as from an examination of the records 

 themselves, there is a very decided lack of 

 good strong evidence as to exact tempera- 

 tures and the kinds of organisms occurring 

 at the temperatures given or hinted at. 

 The records are largely of isolated obser- 

 vationSj generallj^ made incidentally and 

 without, in any case, being a portion of 

 any extensive work to determine tempera- 

 ture limits. As far as the litei-ature goes, 

 there seems to have been nothing sys- 

 tematic attempted along these lines. 



It has been my own good fortune to 

 study with considerable care and thorough- 

 ness the thermal organisms of several dis- 

 tinct regions. The first observations were 

 made at the Arrowhead and Waterman 

 Hot Springs near San Bernardino, Cali- 

 fornia, being introduced to them through 

 the kindness of Mr. S. B. Parish of that 

 city. The visits made to these springs 

 were three in number, in as many different 

 years. The organisms of the hot waters 

 of the so-called geysers in Sonoma County, 

 California, as well as those of several minor 

 hot springs near Calistoga, in Napa County 

 of the same state, were collected and the 

 temperatures carefully noted in June, 

 1900. In August, 1898, ten days were 

 spent in the Yellowstone National Park, 

 under the auspices of the United States 

 Geological Survey, examining the life in 

 the hot waters of the Mammoth Hot 

 Springs, the Norris, Lower, Middle and 

 Upper Geyser Basins, the Lakeshore Hot 

 Springs, and of other lesser collections of 



springs. In all, several hundreds of gath- 

 erings have been made, the specimens care- 

 fully preserved and studied, and the re- 

 sults are awaiting publication. Among 

 other things, especial care was taken to 

 determine accurately and record the exact 

 temperature at which each specimen was 

 growing, so that the data of this character 

 might be complete for the whole series. 

 Not only were the highest temperatures at 

 which living organisms were found, taken, 

 but the temperatures of all organisms in- 

 habiting strictly thermal waters. The re- 

 sults of all my own observations agree 

 perfectly and present a series of facts 

 somewhat at variance, at least in certain 

 essential details, with the results of other 

 observations as tabulated by Davenport. 

 Many, or even the large majority, of the 

 discrepancies disappear, or may be plaus- 

 ibly explained, however, when one con- 

 siders how erroneous certain temperature 

 observations may be, unless taken with 

 certain precautions. 



In my own work it was found very soon 

 that, unless very considerable care was 

 exercised, the temperatures were not those 

 at which the organism was living. It was 

 found, for instance, that it was extremely 

 misleading to take the temperature of a 

 spring and then credit the temperature of 

 any organism existing at any distance from 

 that point as being the same. The central 

 portion of a spring with shallow margins 

 may be of a considerably higher tempera- 

 ture than the margins. In the case of 

 streams, the temperature of two points 

 only a few centimeters distant from one 

 another may diifer 10°-15° C. on account 

 of currents imperceptible except to the 

 thermometer. Especially is this likely to 

 be the ease in springs or overflows into 

 which colder currents come from side 

 streams, whether these be of thermal or 

 cold waters. The temperatures of masses 



