200 Al^IMAL LIFE AND HUMAN PEOGEESS 



red specks were examined microscopically and determined 

 to be the Copepod Temora longicornis, while an examination of 

 the herrings caught at the same time — and for days later — 

 showed that their stomachs were crammed full of a reddish 

 mush which microscopic examination showed to be the 

 partially digested bodies, legs, tails and other parts of the 

 same Copepod. 



Other similar cases have been demonstrated ; and Dr. 

 Allen, at the Plymouth Marine Laboratory, has shown that 

 mackerel fisheries in the Enghsh Channel are connected with 

 swarms of the Copepod CalanusfMmarcMcus, and that Copepod 

 with the prevalence of sunshine — an intermediate link being 

 probably the Diatoms upon which the Calanus feeds and 

 which depend upon the energy derived from sunhght for their 

 nutrition. 



The herring and the mackerel, then, get their abundance 

 of fat— their oily flesh — from the oil globules which are so 

 abundant in their food, the Copepoda, and the Copepoda 

 manufacture their oil and other substances from the Diatoms 

 and other minute organisms upon which they feed, while the 

 Diatoms, being plants, build up their Uving protoplasm by 

 photosynthesis from simpler inorganic substances, getting their 

 carbon, for example, from the carbon dioxide in the sea- water. 

 As on land, so in the sea, all the animals are ultimately de- 

 pendent upon plants for their nutrition, and the plants are 

 similarly dependent upon their inorganic environment. So 

 far as regards organic food, the plants are the producers and 

 the animals the consumers, and the pastures of the sea are no 

 less real and no less necessary than those of the land. 



A few years ago Professor Benjamin Moore carried out, at 

 the Port Erin Biological Station, an interesting investigation 

 on the variations in the alkalinity of the sea-water throughout 

 the year, in which he showed that an increase in alkalinity is 

 due to the relative absence or reduction in the amount of 

 carbon dioxide present, and is really a measure of the conver- 

 sion of inorganic carbon into the carbon present in the bodies 

 of living organisms, and especially in the Diatoms which develop 

 in enormous quantities in the early spring under the influence 



