Dr. Waller on the Origin of Mucus and Pus-globules. 397 



taken with substances whose per-centages of water and nitro- 

 gen had been ascertained. 



Because theoretical equivalents have been employed in con- 

 ditions unequally suited to digestion. The same food, coarse 

 or fine, fresh or prepared for easy digestion, yields unequal 

 measures of nutrition. 



Because the conditions, whether exposed to the open air or 

 protected in stalls, whether subjected to labour of uniform 

 severity, or allowed the free range of pastures, have not been 

 made alike. 



Finally, because, as above intimated, some animals by na- 

 ture differ greatly from others, in the facility with which fat 

 and muscle are developed, even when the circumstances are 

 precisely the same. 



LVIII. Microscopic Observations on the Perforation of the Ca- 

 pillaries by the Corpuscles of the Blood, and on the 0?igin 

 of Mucus and Pus-globules. By A ugustus Waller, M.Z>.* 

 [Continued from p. 287-] 



IN the preceding Number of this Journal I have already given 

 a brief outline of some observations respecting the manner 

 in which the white corpuscles of the blood are seen to leave 

 the interior of the capillary vessels. As this subject is inti- 

 mately connected with the formation or origin of the globules 

 found in mucus and purulent matter, it deserves a close and 

 strict investigation. 



In the first place, we must bear in mind that the blood con- 

 sists of transparent fluid parts containing two kinds of particles 

 in suspension ; the one of a red colour and a flattened disc-like 

 shape, and the other nearly transparent and spherical. The 

 examination of the tongue of the frog, or of any other trans- 

 parent part of a living animal, shows these globules and cor- 

 puscles generally circulating together through the capillaries. 



The examination of mucus and purulent matter shows that 

 they contain great quantities of globules, which are exactly 

 similar to the spherical corpuscles found in the blood. In all 

 these instances these particles are of a spherical form, trans- 

 parent or whitish, granulated, and about the size of t ^q th of a 

 millimetre. In acetic acid they contract, in the alkalies they 

 are quickly broken up, in water they swell and are disaggre- 

 gated into separate minute granules. 



The corpuscles of blood in the mammiferae and in the frog 

 are found to be of about the same size as in man. 



In proof of what I have stated respecting the similarity of 

 * Communicated by the Author. 



