1880.] 



MICEOSCOPICAL JOURNAL. 



113 



intestines and the skin, except in 

 the dermis, but very probably in 

 the liver. This organ was apparent- 

 ly choked wi,th sacculations of an 

 opaque substance, which at first 

 Mr. E. B. Stuart (who rendered in- 

 dispensable assistance) and I, took 

 to be pigment granules, but after 

 slicing by the microtome some sec- 

 tions -^ of an inch thick, and the 

 opacity of these spots persisting, 

 careful consideration leads us to 

 think these opaque spots are aggre- 

 gations of metallic mercury, held 

 in the hepatic channels. In reflected 

 light the unmistakable glint from 

 mercury globules may be caught. 

 Hoping to discover the courses 

 taken by the metal through the 

 body of the frog, I administered a 

 gramme (15.4 gr.) of finely divided 

 mercury, in albumen, to a male 

 frog. In five hours, globules ap- 

 peared on its back. Dissection 

 showed that the intestines, renal- 

 portal circulation, heart, kidneys, 

 and even the testes, contained nu- 

 merous globules of mercury, and 

 the lympliatic passages were beau- 

 tifully injected with globules much 

 more finely divided. Apparently 

 the smaller particles had passed in- 

 to the lymph channels, or the metal 

 had undergone further division 

 in absorption into these passages. 



At 10 A. M. I gave five grains of 

 calomel to a chicken weighing four 

 and a-lialf pounds, eighteen months 

 old. At noon it was sick and very 

 thirsty; at 9 P. M. I blew ten 

 grains more calomel into its pharynx, 

 and at 10 o'clock P. M. killed it. 



It ejected four ounces of water 

 from its mouth, mixed with the last 

 dose of calomel, and I recognized 

 black oxide crystals in this liquid, 

 which had apparently formed aljove 

 the crop. I did not expect conver- 

 sion to occur at this point, but the 

 fact indicates the general tendency 

 of mercurials toward decomposition 



everywhere in the body instead of 

 a formation of higher salts. 



The faeces contained mercury 

 globules. Mercury was distin- 

 guishable by the microscope in 

 three out of five parts of the chick- 

 en's blood ; traces of calomel and 

 black oxide were discernible in the 

 proventriculus and gizzard; a few 

 crystals of the black oxide with a 

 great many globules of the metal 

 were found in the upjDer intestine, 

 with only metal lower down ; the 

 liver contained the metal, while the 

 mesenteries held unmistakably large 

 quantities of the globules, ranging 

 downward in sizes from those usu- 

 ally found in blue mass. The liver 

 globules were small, while those in 

 the mesenteries were large. 



Rationally, then, often repeated, 

 small doses of calomel would im- 

 press the general system better by 

 allowing reduction and absorption 

 to occur at intervals, insuring com- 

 plete reduction and absorption, and 

 wide-spread dissemination through 

 circulatory channels. This is no 

 less true of the mercurials in general. 



{To he continued.) 



About Diatoms. 



The trouble encountered by the 

 correspondent (page 84) in finding 

 specific names for diatoms, is one 

 that is encountered by every stu- 

 dent in every branch of natural 

 history, in botany and zoology. It 

 is one that can be overcome only 

 by persevering study and consulta- 

 tion of the original descriptions of 

 fenera and species, and of all that 

 as been written on the same, since 

 it arises from imperfect descrip- 

 tions, from the various opinions of 

 different authors as to what consti- 

 tutes specific or even generic char- 

 acters, and, in the case of micro- 

 scopic objects, in part from the 

 inferior instruments in use. 



