80 Investigations on the Life-History 



average fish, the other an exceptionally thin fish, and in these fish the 

 various organs were carefully weighed and analysed. 



From his previous average tables he calculates what the weight of 

 muscle, ovaries, etc., of these fish would have been on November 1st, 

 and what would have been the proportion of albumin and fats in these 

 organs. Then balancing the condition in August with the supposed 

 condition in November he concludes that the amount of albumin and 

 fat lost from the muscle is more than sufficient to biiild up the ripe 

 ovaries. 



A number of other points of interest are also considered in the 

 enquiry, such as the transference of phosphorus from muscle to ovaries ; 

 the nature of the phosphorus compounds in each, and the nature of the 

 ovarian fluid. Some of these points will have to be dealt with in a later 

 part of this Report, some of them are of merely incidental interest and 

 need not be considered. 



A careful consideration of Miescher's work shows that it leaves 

 untouched several questions of interest, and that the conclusions arrived 

 at are hardly warranted by the evidence produced. 



In the first place it -leaves unconsidered the changes which the fish 

 undergo in passing from the sea up the river, and, therefore, does not 

 deal with the question of how much of the stored material in the fish 

 goes to the formation of the genitalia and how much is used as a 

 source of energy. 



In the second place, in order to arrive at his conclusions, he 

 assumes that from August to November no fresh fish are coming to the 

 Basel water from the sea, since if this were the case his average results 

 could not be applied to the fish analysed. He argues at length against 

 the possibility of such an immigration of lower-water fish on the ground 

 that, if they came, there must be two classes of fish in the upper waters, 

 one poor in material, consisting of the fish which came up in spring, and 

 one richer in material, consisting of the fish which continued to feed in 

 the sea and came up with their genitalia more developed and with a 

 greater supply of nourishment in the muscle. According to Miescher 

 such two classes do not exist. It is, however, possible that the wide 

 divergence in the weights of individual fish noted by him as much as 

 20 or 30 per cent. may be explained by the arrival of these better 

 nourished fish. The observations recorded on p. 75 of this paper show 

 pretty clearly that in the shorter Scottish rivers, fish leaving the sea in 

 August do pass to the upper reaches. Again, in this argument he makes 

 the assumption, which he does not attempt to prove, that fish continue 

 to feed in the sea all through the autumn. 



The conclusions which Miescher bases upon his analyses are so far- 

 reaching and important that they must be considered with critical care. 

 It seems hardly justifiable to base such conclusions upon so limited a 

 number of observations. Still less is it safe to assume that any two 

 particular cases will accord strictly with the average results. It must 

 be remembered that the detailed examination of only two fish is recorded. 

 So far as the analyses are concerned it may safely be concluded that 

 in the hands of so able a chemist these were properly carried out. 

 Two points, however, require to be pointed out. First, that the fats 

 were not directly determined, but that the difference between the total 

 solids and the albumin was taken to represent the fats. Second, for 

 the analyses of the muscle he says (p. 179) " An einer Reihe von Juli 

 und Augustsalmen wurde desshalb, immer von desselben Stelle genom- 

 men, der Eiweissgehalt des grossen Seitenrumpfmuskels bestimmt." 

 Apparently no cognisance was taken of the marked difference between 

 the trunk muscle generally the " thick " of the fish and the belly 



