Journal of Applied Microscopy. 



17 



And the following- staining reagents 

 have proven most satisfactory: 



Ranvier's Picro-Carmine or Mayer's 

 Carmalum, for a carmine stain. 



Safranine. 



Acid Methyl Green. 



Ehrlich Biondi Mixture — for an analine 

 stain. 



In case safranine is used, the proced- 

 ure should be as follows: Plasmodia 

 hardened, or at least fresh from 90 per 

 cent, alcohol, are placed in the staining 

 solution, overstained and then decolor- 

 ized in 80 per cent, alcohol until nearly 

 ready to mount, when they are trans- 

 ferred hastily through absolute alcohol 

 to clove oil, which completes the extrac- 

 tion of color, and from this they are 

 mounted in balsam. 



Another procedure is as follows: From 

 the decolorizing 80 per cent, alcohol, they 

 are transferred to a mixture of 1-3 each 

 of carbolic acid, bergamot and cedar 

 oils, and from this into balsam. 



SECTIONS OF PLASMODIA AND SPORANGIA. 



After killing, fixing and transferring 

 to the permanent bath of alcohol or for- 

 malin, Plasmodia are ready for imbed- 

 ding and they give excellent preparations 

 by both the paraffin and celloidin meth- 

 ods, but I much prefer the latter pro- 

 cedure on account of the mojre natural 

 condition of the protoplasm when it 

 finally comes under the lens for study. 



There is no difficulty in getting suit- 

 able masses of the mature and fruiting 

 sporangia forming Plasmodia for study, 

 but sometimes it is not easy to get the 

 young Plasmodia in large enough masses 

 for satisfactory sections. Young Plas- 

 modia may be coaxed to heap them- 

 selves up into cavities in filter or blot- 

 ting paper by wetting the paper with 

 nutrient solution, and forming- it into 

 suitable thimble or cup shaped recep- 

 tacle it may be dropped into any of the 

 killing and fixing media and good pre- 

 parations secured. 



Serial sections may be treated with 

 different stains, a slide at a time, and 

 the results of different reagents thus 

 observed upon the same mass of pro- 

 toplasm. 



MYXAMOEBAE. 



The very young or incipient Plasmodia 

 and the myxamoebae should be treated 

 with the methods employed in the 

 study of rhizopoda. They may be col- 

 lected in numbers in watch glasses or 

 in culture cells and killed in loco, or 

 transferred to slide covered and treated 

 with the required succession of reagents 

 by means of the washing apparatus 

 shown in Fig. 1. 



A METHOD OF QUICKLY AND ACCURATELY 



MARKING THE POSITION OF AN OB- 



.lECT IN THE FIELD. 



With a Ring of Varnish. — The posi- 

 tion of particular nuclei, granules, 

 food vacuoles or any o^bject what- 

 soever may be quickly marked upon 

 the surface of the cover g-lass with a 

 ring by attaching- to the end of 

 the object glass a collar bearing a cen- 

 tered ring as shown in Fig. 2. If a 



Ri-f" 



triple or quadruple nosepiece is attached 

 to the microscope it will be found con- 

 venient to use one opening for a blank 

 objective provided with such a marker. 

 The microscope tube is lowered until 

 the ring deposits a thin layer of varnish 

 on its lower edge upon the cover glass. 



"With a Minute Dot of India Ink.— For 

 many preparations it is preferable 

 to mark the positions of the objects 

 elected by a small black mark such as 

 may readily be produced by having a 

 needle or quill point mounted in the 

 center of such a collar as mentioned in 

 the last paragraph. The ink is applied 

 by means of a quill or brush which 

 comes in all bottles of the fluid, and the 

 microscope tube is then lowered until 

 the point deposits the small dot of ink. 



With a Triangular Paper Label. — If it is 

 desired to use a white mark, min- 

 ute triangles of paper may be cut 

 and placed upon a very small drop 

 of mucilage or balsani which has been 

 placed upon the cover glass by means 

 of the point used for marking with ink. 

 When the fixative is dry, such white 

 labels serve to mark the position of ob- 

 jects very clearly. The ring should be 

 made of light spring brass, as the whole 

 instrument may be made from one 

 piece. 



