Very large specimens of Salpa maxima flatten out their 

 own weight when put into weak alcohol. This may be obviated 

 by blowing a few bubbles of air into the cavity of the animal 

 or by putting therein a tube of thin glass closed at both ends 

 to act as a float. The tube or the bubbles of air should be 

 removed before the animal is entirely hardened. 



Professor Todaro, to preserve Salpas for histological 

 purposes, immerses them at first in Kleinenberg ' s solution, 

 and after an hour transfers them to alcohol. When preserved 

 in this manner, however, all but the hard species lose their 

 form entirely. 



One can easily inject the circulatory system of living 

 Salpas with Prussian blue by placing the point of a fine syringe 

 in the slender canal of the heart and operating it with a very 

 gentle pressure. After this the animals can be treated by the 

 methods already detailed, and the color will remain very well 

 after they have been put into alcohol. 



The Doliolids give good preparations when killed with the 

 mixture of sulphate of copper and sublimate, saturated sublimate 

 alone, or with the chrom-osmic mixture. After a few minutes wash 

 the animals thoroughly with fresh water and transfer them gradu- 

 ally to 70 per cent alcohol. 



Fish 



In general, fish present no difficulties in their pre- 

 paration. If possible, they should be alive when put into the 

 fixing fluid, because thus only do they preserve the shape of 

 the body well and keep the fins completely distended. Those 

 which have been dead for some time and have been left to dry, 

 having already lost much water, have the fins contracted and 

 dried, and when placed in alcohol they contract still more. To 

 preserve dead fish for anatomical purposes, inject them first 

 through the anus with 90 per cent alcohol and then put them into 

 that of 70 per cent. 



To prepare Amphioxus with the mouth cirrhi distended, the 

 animals are allowed to die in sea water alcoholized to 10 per 

 cent, and after death, which usually occurs in a few minutes, 

 they are transferred to alcohol of 50 per cent, and gradually to 

 that of 70 per cent. Muller's solution 1 can also be used for 

 killing, if suitable for the purpose for which the animals are 

 intended; but they remain colored, and often swellings are formed 

 in the sides of the body. Chromic acid of 1 per cent is sometimes 



Potassium bichromate, 2 grams; sodium sulphate, 1 gram; distill- 

 ed water, 100 grams. 



2138— No. 39, Pt. M 4 



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