970 KEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



it Closely related to Clathrocystis aeruginosa^ a common species growing 

 in fresh- water ponds, which has lately come into public notice in conse- 

 quence of the so-called ^i^-jpe?i odor which it exhales when decaying. 



The ClatJirocystis in question belongs to the lowest group of plants, 

 the Schizojihytw, many of which are the cause of decomposition or putre- 

 faction of diiierent animal and vegetable substances. Clathrocystis 

 roseo-persicina is very widely diffused, being known both in Europe and 

 America. It is found in summer along our shores, and at times is so 

 abundant as to cover the ground with a purplish tinge, as one may see 

 in the marshes near Lynn. It is also known in dissecting-rooms, where 

 it grows in tubs in which bones are macerating. Wherever found it 

 does not flourish nor increase rapidly at a temj)erature below 65° Fahr. 



The next point to be considered is the manner in which the Clathro- 

 cystis is communicated to the fish. An examination of several different 

 packing-houses and the wharves on which the fish are landed showed 

 that the Clathrocystis was present in large quantities on the wood- work 

 of all kinds; on walls, floors, and the flakes on which the fish are 

 laid. How it might have been originally introduced into the build- 

 ings is a question easily answered when we consider how abundant the 

 plant is on the marshes in the vicinity of Gloucester. It might have 

 been brought in on the boots of fishermen, on sea-weed, on grass, or in 

 other evident ways. Once in the buildings it would grow and increase 

 on the damp wood-work, which contains usually more or less animal 

 matter coming from the fish in process of drying. Why the plant is 

 found at times on board the fishing- vessels themselves admits of expla- 

 nation in two ways. It will easily be seen that, when it is common in 

 and around the buildings on the wharves, it would be carried on the 

 feet of fishermen on board the vessels. But there is also another 

 reason why it should be found on the vessels. Large quantities of salt 

 are of course used in packing the fish in the hold of the vessels. The 

 two kinds of salt most commonly used by the fishermen of Gloucester 

 are the Cadiz and the Trapani. I procured specimens of both kinds 

 and submitted them to microscopic analysis. The Cadiz salt has a 

 slight rose-colored tinge; the Trai)ani is nearly a pure white. The 

 microscope shows that the reddish color of the Cadiz salt is owing to 

 the presence in considerable quantities of precisely the same minute 

 plant which is found in the red fish. The Trapani is a much purer salt, 

 and the Clathrocystis^ if it is found in it at all, exists in very small 

 quantities. What must happen then is plain. The Cadiz salt, as it 

 comes into the hands of fishermen, is akeady impregnated with a con- 

 siderable quantity of the Clathrocystis. It is sprinkled in large quan- 

 tities upon the fish as they are packed in the hold of the vessel, and if 

 the weather is warm enough for the favorable growth of the plant, 

 which, fortunately for the fishermen, is not the case in this latitude 

 except for a short period, the fish must inevitably be affected during 

 the voyage. As soon as the fish are landed, the circumstances are 



