392 SCIENCE PROGRESS. 



and aret in fact more abundant on them than in the sur- 

 rounding waters. The forms peculiar to the high seas are 

 of a very few species, but these have a wide distribution. 

 From the fact of this general distribution and their develop- 

 ment on dead animals and plants, Fischer makes the safe 

 inference that they play the great and necessary part of 

 putrefactive organisms in the economy of the sea, keeping 

 the waters from becoming choked with dead organic 

 matter, breaking this up and restoring it to circulation. 

 There is as yet no evidence that the sea bacteria are able 

 to cause diseases in the bodies of marine animals. Inocula- 

 tion experiments by which the luminous forms caused the 

 death of mice (the bodies of which subsequently exhibited 

 phosphorescence) ma\' be significant or may be misleading- 

 just as one is sanguine or cautious. The whole investigation 

 of marine bacteria is yet in its infancy, and comparatively 

 local in its results, but its advancement will undoubtedly 

 throw an interesting light on the general study of these 

 organisms. 



Dr. Schutt, who with Dr. Fischer was one of the 

 naturalists of the German Plankton Expedition, has made 

 a. minute and careful study of the little-known group of 

 PeridiniiiE (4 and 5), which form, together with the 

 diatoms, the great bulk of free-fioating marine vegetation, 

 •especially in temperate regions and near coasts. They are 

 familiar to all from being the source of the luminosity or 

 phosphorescence of our seas in summer and autumn. While 

 diatoms are most abundant in our seas in the spring months, 

 there are very few Pcridinie(^. In summer and autumn the 

 ■diatoms, though still plentiful, gi\e place to enormous 

 quantities of Pei'idiniece which continue fairly abundant 

 until about December, when they wane before the gradual 

 predominance of diatoms again. They are a remarkable 

 group, and our knowledge of their structure is due more to 

 zoologists than to botanists from the rooted disinclination 

 of the latter to use tow-net and microscopes at sea. The 

 shore-loving botanist, however, will have to find his sea- 

 legs before long, since so many problems are being sub- 

 mitted to him by the few who have ventured on the ocean 



