PROGBESS OF MICROSCOPICAL SCIENCE. 120 



ber. Among his observations tlie following seems of interest. He 

 says that in making experiments with blood corpuscles he has lately 

 noticed that if a drop of blood, freshly drawn, be placed in an alkaline 

 solution of carmine, the red corpuscles lose their power of forming 

 rouleaux, and the white corpuscles absorb the carmine, seek each 

 other, congregate in little masses, and seem to become agglutinated to 

 each other. In a drop of blood prepared for microscopic inspection, 

 by careful focussing there can be seen the whole field covered by 

 fine little rings, which seem to form a delicate network, looking 

 somewhat like the cornea of a fly seen with a low power ; this is 

 nothing but the red corpuscles of the blood which touch each other 

 by their edges. Scattered over this delicate, pale network, there can 

 be seen, here and there, little, bright red, cellular masses ; these are 

 the white corpuscles of the blood tinged with carmine. In specimens 

 of pathological urine he has also seen sometimes, under the micro- 

 scope, that pus-corpuscles have a tendency to approach each other, 

 and to form adherent masses. Perhaps the foi-mation of miliary 

 tubercles takes place in a similar manner. The amceboid cells, when 

 leaving the circulation, may bring with them a tendency to form into 

 granulations, or the chemical or physical condition of the surrounding 

 tissues may determine them to assume the form of minute nodules. 

 We find sometimes, with these semi-transparent bodies, others rather 

 of a fibrinous structure ; they may represent a subsequent stage in 

 the development of tubercularization. The lymphoid cells may have 

 changed into fibrinous tissue by progressive metamorphosis. Virchow 

 thinks that the fibrinous tissue represents the first stage of tubercular 

 growth, which has not yet unfolded itself into tlie full-blown cellular 

 tubercle. Langhaus, on the contrary, looks upon this formation as 

 the full development of the cellular tubercle, and describes it as con- 

 sisting of three zones, formed by the transformation of round cells 

 into fibrillas. "Whether such bodies can be distinguished from minute 

 fibromas, or whetlier the one or the other be the earlier stage of a 

 continuous development, the tendency of all tubercular deposits to 

 sj^eedy decay has been universally recognized. Virchow says : " This 

 structure, which in its development is most nearly related to pus, 

 inasmuch as it has the smallest nuclei, and relatively the smallest 

 cells, is distinguished from other more highly-organized forms of 

 cancer, cancroid, and sarcoma, by the circumstance that these contain 

 large voluminous corpuscles, with highly-developed nuclei and nu- 

 cleoli. Tubercles, on the contrary, are always a pitiful production, 

 and from the very outset perishable." And in this respect, also, 

 tubercle betrays its origin and nature. The paper is of considerable 

 length, and sums up the researches that have been made already on 

 tlie subject. 



Tlie Young of Cliironedes pictus. — A letter from Professor Agassiz 

 is published in ' Silliman's American Journal of Science and Art ' for 

 February (1872), wliich is of great interest, as it tells us a good deal 

 about tlie yoimg of this fish. The letter is to Professor Pierce, and after 

 some preliminary details of the nature of the nest, &c., which was found 

 in the Gulf Stream, it says that a more careful examination very soon 



