THE SALT-WATER FISHERIES OF BOHUSLAN. 161 



places. The most extensive and most complete number of observations 

 will bring our knowledge as near actual truth as possible. It wiU be 

 self-evident that whenever, as in the case of the fisheries, we have to do 

 with periodical changes embracing long periods of time, there will be 

 special need of many and long-continued observations. 



3. But as such entirely sufficient material is for the present not 

 accessible, and could not possibly be procured during the comparatively 

 short time which I have been able to devote to the investigation of the 

 herrings and the herring-fisheries on the western coast of Sweden,^^ even 

 if I had had ever so many able assistants, I cannot do better than to use 

 the material on hand, which, certainly from a scientific point of view, is in- 

 sufficient, but wliich, nevertheless, j)ossesses some i)ractical value. Even 

 the most careful preparation of this heterogeneous mass of material 

 must, however, be defective, because no satisfactory result can be reached, 

 unless we possess a thorough knowledge of all the points based on the most 

 comprehensive scientific material, xilthough, in a work like the present, 

 it may be important to give in each case the exact source from which 

 the information has been drawn, I have thought fit to deviate from this 

 generally observed rule, chiefly because it is my intention to treat the 

 whole subject more fully in a larger work which I am preparing, the title 

 of which will be "On the Herring and the Herring-Fisheries," and also 

 to reduce the time^^ and cost of this brief review as much as possible. 

 I nevertheless hope that this little work may be of some use, and prove 

 a help to those of our writers on the fishery-question who by different 

 circumstances are confined to the observations of others. 



4. Natiu-al science, considered as a systematic review of all nature, is 

 constantly growing more many-sided and more complicated, in propor- 

 tion as it develops and as it is simplified by having many different facts 

 condensed into general axioms (" Les scienceH progressent en se simplifianf,''^ 

 Leibnitz). Nature forms a continuous whole, all parts of which are con- 

 nected by an indissoluble causal connection both among themselves and 

 with the constantly developing universe ; the scientific investigation of 

 a natural object or a natural phenomenon can reach completeness only 

 in proportion as it is many-sided. It is a very common mistake to view 

 the different phenomena isolated from others; and science suffers in 

 consequence, entire systems being built on such incomplete views, which 

 may for the time being satisfy at least the less scientific and critical 

 portion of the public, but which are very hard to root out, all the harder 



*^ Since July, 1873, 1 have (commissioned by the government) been bnsy in collecting 

 such scientific data regarding the natural history of the herring and the herring-fish- 

 eries as I deemed necessary for improved legislation on our herring-fisheries. 



*^The greatest difficulty has been experienced and almost insurmoiintable hinderances 

 placed in the way of gaining the necessary time for a "work like the present, by the 

 necessity of carrying on simultaneously the investigations regarding the other por- 

 tions of the biology of the herring, and the many other different points in this whole 

 herring question, the legislative, administrative, and economical parts of which have 

 taken up the greater portion of my time spent on the coast of Bohusliin. 

 11 P 



