466 Journal of Applied Microscopy. 



xylol and wash the slide with 85 per cent, alcohol for a minute or two to 

 remove the xylol. Place the slide in the stain, which is prepared as follows : 

 Dissolve 0.3 g. dry methelyn-blue in '250 cc. distilled water. Add to this 0.1 g. 

 or 0.2 g. of any good uncolored castile soap. Allow this to dissolve and filter 

 the mixture. Place the slide in a crystallizing dish which contains the stain. 

 Set the dish on a bath or stove where its temperature can be kept at from 

 55 to 60 degrees C. Four or five hours is sufficient to stain the sections, 

 although they do not overstain easily. A differentiating fluid is made from 

 90 parts absolute alcohol and 10 parts anilin oil. When no more blue color 

 is given off, the sections may be cleared in oil of cajuput, and mounted in xylol 

 balsam. So far, I do not find that this mounting medium affects the stain. 

 Nerve cells and their processes should show a rich blue stain, and their 

 nuclei a yet darker stain. Fiber tissue should remain unstained, but can be 

 followed with ease, as the tissues are well preserved. Fresh tissue is required to 

 begin with, as old tissue fails of differentiation. The method applies equally 

 well to the spinal cord, and to nerves. Good, clear outlines of ganglionic cells 

 can be obtained, even with an oil immersion lens, in the 20 /< sections. 



Earl Ramsey. 

 Biological Laboratory, University of Indiana. 



A Convenient Source of Gregarinidae. 



We may safely assume that nowadays every teacher of biology has had his 

 students study amoebae, for if he follow the directions of most guides, he cannot 

 fail to find them. One such book naively directs : " Take a drop of water con- 

 taining amoebae . . . ," in which case, of course, you cannot fail. 



If it were more generally known how easily Gregarines may be obtained and 

 kept "in stock," I believe they would be more often used for comparison, and as 

 representatives of parasitic protozoa. Teacher-like, we gladly pass a good thing 

 along. 



Gregarinidae may be found more or less abundant (usually less when you 

 come to look for them) in the intestines of insects, and of other invertebrates. 

 But in the alimentary tract of the yellow jointed larvae of Tenebrio molitor they 

 may be found at all times, and in abundance. This is the black beetle found in 

 granaries, mills, barns, etc. Its larvae, commonly known as meal-worms, and 

 often erroneously called wire-worms, may be found in abundance in flouring 

 mills, feed stores, under boards and bags that have lain for several months, or 

 under feed-boxes in stables — anywhere, in fact, where ground grain is stored. 

 The best time is when repairs are being made in a neighboring mill. 



For keeping, place the larvae in glass or stone jars, with plenty of the grain 

 debris in which they are found, occasionally adding more meal, some dry-rotten 

 wood, rags, etc., and they may be kept almost indefinitely without farther atten- 

 tion. If too well fed they metamorphose rapidly, at certain times of the year, 

 and by keeping the jar covered, the beetles depositing eggs produce a new brood, 

 but this is likely to deplete the stock. 



At present I have a fruit jar half full of debris containing several hundred 



