LYSOZYME 



142 



MACROPHAGES 



method for its determination in lympho- 

 cytes and polymorphonuclear leuco- 

 cytes (neutrophiles) is given by Barnes, 

 J. M., Brit. J. Exp. Path., 1940, 21, 264- 

 275). The use of lysozyme as a cyto- 

 logical agent in bacteriology is de- 

 scribed by Dubos, R. J., The Bacterial 

 Cell. Harvard Univ. Press, 1945, 460 pp. 

 Observation that a bacterium is sus- 

 ceptible to lysozyme is an indication 

 that it contains as an essential part of 

 its structure a substrate for this en- 

 zyme, probably an acetyl amino pol- 

 ysaccharide. 

 Lyssa Bodies are small Negri bodies which 

 look optically hyaline, see Negri Bodies. 



Maceration (L. macerare, to soak) is a very 

 important technique by which tissues 

 are soaked for considerable periods of 

 time in various fluids which loosen the 

 connections between the cells and allow 

 them to be easily separated for micro- 

 scopic study. This is a method em- 

 ployed by the great masters in histology 

 which is unfortunately not sufficiently 

 used now-a-days. 



For nervous tissue Addison (McClung, 

 p. 439) recommends Gage's dissociator 

 which is 2 cc. formalin in 1000 cc. 

 physiological salt solution for 2 or 3 

 days. After this treatment large ven- 

 tral horn nerve cells can easily be dis- 

 sected out with the aid of a binocular 

 microscope, stained with carmine, picro- 

 carmine or a dilute anilin dj'e and 

 viewed as units with parts of their 

 processes attached. 



Smooth muscle of the bladder is well 

 dissociated by 10-20% nitric acid 

 (Dahlgren, in McClung, p. 423). The 

 resulting fibers are suitable for class use. 



Thyroid follicles are freed from the 

 surrounding tissue and can be examined 

 individually after maceration in cone, 

 hydrochloric acid 3 parts and aq. dest. 

 1 part for about 24 hrs. and thorough 

 washing in at least 10 changes of tap 

 water (Jackson, J. L., Anat. Rec, 1931, 

 48, 219-239). 



Epidermis can be separated from 

 dermis by maceration in 1% acetic acid, 

 see epidermis. 



Kidney tubides. Pieces of kidney 

 fixed in 10% formalin or in Kaiserling's 

 solution are placed in cone, hydrochloric 

 acid at room temperature until they 

 become sufficiently softened after 2-7 

 days. The time depends upon size of 

 piece, degree of fibrosis and other factors. 

 There is no advantage in using fresh 

 tissue. When adequately macerated 

 the almost diffluent tissue is washed in 

 repeated changes of aq. dest. in which 

 it may be kept for several days. Dis- 

 sect out individual tubules with the 



aid of a binocular microscope (Oliver, 

 J. and Luey, A. S., Arch. Path., 1934, 

 18,J77-816). 



Seminiferous tubules. Whole human 

 testicles are fixed in formalin. They 

 are then cut into segments 1 cm. thick 

 parallel to direction of the lobules. The 

 tunica vaginalis is not removed but is 

 slit through in one or two places with a 

 razor. Each segment is placed in cone, 

 hydrochloric acid, 75 cc, aq. dest. 25 cc. 

 1-7 days. Heat just below boiling 

 20-30 min. Tissue shrinks, turns dark 

 brown and softens. A sediment collects 

 in the dish. Part of acid is drawn off 

 with a pipette, boiled water is added 

 and the process is repeated until practi- 

 cally all of the acid is removed. The 

 water is boiled to prevent formation of 

 air bubbles along the tubules. It turns 

 the tubules a yellowish white color in 

 which condition they should be isolated 

 by careful teasing. When the tubules 

 cannot be easily lifted away from one 

 another, the maceration is insufficient. 

 When, on the other hand, they break 

 it is a sign of over maceration (Johnson, 

 F. P., Anat. Rec, 1934, 59, 187-199). 

 A similar method was used by Johnson 

 in 1916 to separate the lobules of the 

 pig's liver. 



Bo7ie cells and lamellae. Treat a 

 thin bone section with cone nitric 

 acid as long as 24 hrs. Mount on a 

 slide and squeeze out bone cells by pres- 

 sure on cover glass. The lamellae can 

 be pealed off easily from a piece of 

 decalcified bone which has been gently 

 boiled in water (Shipley, in McClung, 

 p. 348). 



Enamel rods. A piece of dental ena- 

 mel is dissociated with 5-10% hydro- 

 chloric acid for 24 hrs. When it has 

 become soft, remove a little with a 

 needle to a slide and tease out. Mount 

 in physiological salt solution under a 

 cover glass. Draw through a little 

 carmine stain with a blotter and wash 

 it out with 10% acetic acid. The 

 specimen can be ringed with paraffin 

 (Churchill, and Appleton, in McClung, 

 p. 372). 



Nerve cells. Pieces of gray matter 



of ventral horn are soaked for 2 or 3 



days in 0.02 formalin. The tissue 



softens, the cells are dissected out and 



stained with carmine or picro-carmine 



(Addison, in McClung, p. 439). 



MacNeal's Tetrachrome is a blood stain 



containing eosin, methylene azure A, 



methylene blue and methylene violet. 



It is employed like Wright's stain. 



For details see MacNeal, W. J., J. A. 



M. A., 1922, 78, 1122, and Conn, H. J., 



Stain Technology, 1927, 2, 31. 



Macrophages. These are the free cells of 



