1884.] 



MICROSCOPICAL JOURNAL. 



179 



crop of fine brick-dust-red crystals . These 

 should be collected, thoroughly dried,. and 

 preserved. When required for use, dis- 

 solve in about 50 times their weight of 

 distilled water, filter the solution, and 

 keep in glass-stoppered vials. Do not 

 make more than an ounce of the solu- 

 tion at once, as a little of it goes a long 

 way.' 



— Photography with the microscope has 

 become so popular among our readers 

 that we doubt not many of them have 

 found it troublesome to prepare the de- 

 veloper, and are often thereby deterred 

 from making an exposure in the camera. 

 A ready-mixed developer that will keep 

 indefinitely will meet with a glad welcome 

 from such persons, and we are glad to 

 call attention once more to the pyro- 

 developer prepared by Mr. Walmsley. 

 It is an excellent combination for general 

 use, and is always ready for instant use. 

 It gives clear negatives, and if the expos- 

 ures are not inordinately short for the 

 plates used, they are free from color. 

 Pyro-developers are more generally used 

 in England than here, but they seem to 

 be growing in favor. Mr. Walmsley has 

 just returned from a trip abroad, and will 

 hereafter keep a stock of dry plates from 

 celebrated English manufacturers. 



— Dr. Frank L. James, who conducts a 

 microscopical column in the Natio7ial 

 Druggist, gives the following instructions 

 for making a neutral-tint camera lucida : — 



' It is merely a No. 2 three-quarter-inch 

 round cover-glass inserted at an angle of 

 forty-five degrees into a holder which 

 embraces the rim of the eye-piece. Any 

 person can make one in three minutes 

 with a pill-box and a cover-glass. Pro- 

 cure a box that fits over the eye-piece 

 snugly, cut a hole in the bottom the size 

 of the front lens, and just below it make 

 a horizontal slit a quarter or three-eighths 

 inches long by driving a penknife blade 

 through the bottom at an angle of forty- 

 five degrees. Stick your cover-glass in 

 this, and you have a neutral-tint camera 

 lucida.' 



— Mr. Woolman has recently received 

 a series of mounted sections of rocks, 

 which are probably as good as have been 

 seen, if not even better than any hereto- 

 fore placed upon the market. They are 

 prepared by A. Hensoldt, London and 

 Wetzlar, and compare favorably in price 

 with those of inferior quality. 



— Dr. D. E. Salmon, the chief of the 

 Bureau of Animal Industry, has reported 



a number of cases of contagious pleuro- 

 pneumonia among cattle in the West. 

 This is a disease which may well cause 

 alarm among stock-raisers, and although 

 there is reason to fear it has already been 

 extensively diffused, it is encouraging to 

 notice the prompt action of the authorities 

 of different States to prevent its further 

 progress. Dr. Salmon is now in Chicago, 

 where he is laboring hard to stamp out 

 the disease, in which, we trust, he will be 

 successful. 



' — Mr. G. D. Julien offers sections of 

 rocks, minerals, fossils, etc., in our ad- 

 vertising columns which are undoubtedly 

 excellent. We say this much without 

 having seen them, but with the facilities 

 for preparing them at the School of Mines, 

 where Mr. A. A. Julien has prepared 

 many hundred sections for study, there 

 is no reason why specimens of the best 

 quality should not be prepared for the 

 use of microscopists generally. 



— A committee of the A. A. A. S. was 

 appointed at the Philadelphia meeting to 

 endeavor to secure Government aid in the 

 investigation of fungoid diseases. The 

 subject is one well worthy of liberal as- 

 sistance, and its importance need not be 

 urged. Few persons realize, however, 

 the necessity of assistance, and it is hoped 

 the committee will clearly set forth the 

 -difficulties which interfere with, and al- 

 most entirely prevent, the carrying out of 

 private investigations in this direction. 

 The work is of peculiar difficulty, requir- 

 ing constant attention on the part of the 

 observer, and it is not only necessary to 

 have special laboratories properly fur- 

 nished for it, but skilful and experienced 

 observers must be engaged, who can give 

 their entire attention to the work. We 

 shall watch with interest the efforts of 

 the committee. Their efforts should be 

 crowned with success, for even the pub- 

 lic at large now manifests such an inter- 

 est in the observations of microscopists 

 upon the causes of disease that it may 

 reasonably be supposed Congressmen will 

 easily be convinced of the importance of 

 the work. 



CORRESPONDENCE. 



A Long Worm in a Grasshopper. 



To THE Editor : — Recently, while dis- 

 secting a grasshopper, I discovered within 

 its body a worm, evidently parasitic, which, 

 after being removed and unfolded, meas- 

 l ured twenty-one and one-half inches in 



