272 MEMORANDA. 



sists in the materials for making the blue, the other in- 

 gredients are similar to his, and we have found them to 

 form an admirable combination for suspending the insoluble 

 and minutely divided precipitate. 



In order to mount injections made with the Tumbull's blue, 

 the following plan is recommended : 



If the injected sections will bear it, they should be well and 

 repeatedly washed with cold water. Portions of the kidney, 

 for instance, we have left in water for three or four days, 

 changing the latter frequently during the period. When 

 thoroughly washed, they should be placed, for a week or 

 more, in glycerine, acidified with dilute muriatic acid, and, 

 lastly, mounted, in cells with some of the following solution. 



Composition of the preservative fluid for the blue in- 

 jections : 



Glycerine (Price's) .... 5 drachms. 



Creasote and naphtha fluid (Beale's*) . \ drachm. 



Dilute muriatic acid .... a trace. 

 Mix. 

 — Ben. Wills Richardson, F.R.C.S.I., Dublin. 



On Extravasations of Blood, and the production of Aneurisms 

 caused by Parasites.— An interesting paper on this subject, 

 chiefly with reference to appearances often observed in the 

 frog, is published (Reichert and Du Bois Reyinond's 

 ' Archiv' for 1860, p. 195) by Louis Waldenburg. The con- 

 clusions at which the author arrives are the following : 



1. The hsematode cysts of the frog contain altered blood, 

 due to extravasations produced by nematode worms which 

 have migrated into the blood-vessels. 



2. The horny filaments met with in the mesentery and 

 coats of the intestine in frogs are bodies of foreign origin, 

 which have gained admission from without into the circula- 

 ting system of the animal. They are lodged in true 

 aneurismal swellings of the blood-vessels caused by their 

 presence, are surrounded by a thrombus, and are at the same 

 time the cause of the numerous minute cysts observed in 

 their vicinity, and which arc also to be regarded as encysted 

 aneurisms. 



3. The pigment-follicles attached to the vessels in the 

 spleen, liver, and kidney of fish, and which contain Psoro- 

 spermia, are also aneurisms caused by animals from whieh 

 the Psnrospermia arc derived, and whieh animal* arc found in 

 the vessels. 



* 'How to Work wit li the Microscope,' p. 30. 



