SEA-FISHERIES LABORATORY. 



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myxosporidian spores. A small portion of the tumour as 

 seen with a high power immersion lens is depicted in 

 fig. 2, pi. VIII. Part of the core of one of the tubercles is 

 shown with a number of the small oval bodies referred to. 

 These have an average length of about 5/ul. They stain 

 densely with eosin or iron haematoxylin, and show no 

 obvious structure. They are not at all numerous. 



The rest of the tissue consists of cells of various sizes, 

 with apparently some structureless material serving as a 

 matrix. There are two* kinds of these cells. One kind 

 stain densely, are rather smaller than the others, and show 

 a definite nucleus The other kind appear also to be 

 nucleated, though it is difficult to be certain, and are 

 larger. Indeed one can easily say too much regarding 

 the cytology of this tissue, for the preservative was only 

 formalin and I had no opportunity of fixing the thing 

 properly. 



I think the only probable explanation of this con- 

 dition is that it represents a catarrh of the skin, such a 

 condition as is described by Hofer* as " Erkaltungs- 

 krankheiten." I have not seen any such condition as is 

 represented by Hofer's plates VIII and IX, but the 

 general " turbidity " of the skin, the delicate waxy bloom 

 which he speaks of, is well shown in some of these 

 specimens. It appears to be a paradox, Hofer says, to 

 speak of a fish as catching cold or catarrh ; still that such 

 an ailment should be experienced by a fish is not so sur- 

 prising as it at first appears to be. In a cold blooded 

 animal the heat regulating mechanism, which is so 

 characteristic and important a feature in the physiological 

 economy of a warm blooded creature, is conspicuously 

 absent. The temperature of a fish is always that of the 

 medium in which it lives, or only a very little higher. 



* Handbuch der Fischkrankheiten, Munchen, 1904, p. 87. 



