210 NOTES AND MEMORANDA. 



being sunk in alcohol without displacement of the liquid 

 portion of the albumen. The mass is ready for cutting 48 

 hours after preparation. The alcohol should, for ordinary 

 purposes, only be changed once, as otherwise the material 

 becomes too hard ; if the alcohol is changed three or four 

 times during the first 24 hours, the mass becomes sooner 

 ready for cutting, and the longer the material remains in 

 the alcohol after the first 48 hours the better does it cut. 

 The sections are made in the ordinary way, with a razor 

 wetted with spirit, and are mounted directly in Canada 

 balsam or damar. The temperature of 70°-75° C, to which 

 tissues are exposed by this method of embedding, causes, 

 according to Dr. Calberla, no marked change in them. 



The great objection to this method of embedding, putting 

 aside the amount of trouble involved in it, and the danger of 

 the alcohol vapour taking fire, is the necessity of preparing the 

 fluid material from eggs every time an object has to be em- 

 bedded, for under ordinary circumstances it rapidly dries up 

 and decomposes. It has been suggested to me that salicylic 

 acid might advantageously be added with a view of keeping 

 the material free from germs, and in a cool place in a stop- 

 pered bottle it will keep even without antiseptics for a fort- 

 night. The service which this material is capable of render- 

 ing is of the very greatest importance. It will be especially 

 valuable for the cutting of sections of minute and friable 

 embryos, giving absolute certainty and corresponding comfort 

 to the student in the preparation of his sections, in place of 

 the anxiety and annoyance due to friable embryos and oily 

 embedding media. Dr. Calberla has earned the gratitude of 

 all embryologists. — D'Arcy Power. 



A Central Agency for the Supply of Microscopic Organisms 

 to Students and Class Teachers. — I have very great pleasure in 

 calHng the attention of the readers of this Journal to the living 

 organisms offered for sale and sent out through the post by 

 Mr. Thomas Bolton, Hyde House, Stourbridge. Mr. Bolton 

 has suppHed me with several dozen specimens of Hydra viriclis 

 for the purpose of class-demonstration, and he expects to be 

 able to supply these polyps at all times of the year. During 

 the month of February he sent me, safely through the post, 

 and at the most reasonable charge, a bottle containing a dozen 

 specimens of yicfinospAcermm Eickornii, an object which the 

 student, whether young or old, can hardly examine too care- 

 fully or too often. Young specimens of Spongilla, a variety of 

 rare and interesting Rotifera, Infusoria, &c., are also offered 

 from time to time by Mr. Bolton as they appear in the ponds 



