<5o HISTOLOGY OF NUTRIENT FLUIDS. 



matter. It cystallizes after being dissolved out of the cor- 

 puscles. Its composition is C. 53.85, H. 7.32.0. 21.84,8. .63, 

 Fe. .42. 



2. Size. Many have attempted measurements of the red 

 corpuscles for the purposes of jurisprudence, but to the present 

 the size is quite uncertain, and the measurements only com- 

 parative and approximate. In every specimen of blood ex- 

 amined with high powers corpuscles are seen which are one- 

 half or one-third smaller than the rest, and the number of 

 these smaller ones is often quite considerable, especially in 

 anaemia and other pathological states. There are also very 

 minute corpuscles which have been termed microcytes, or 

 small cells, but which do not seem to differ otherwise from 

 the larger globules. The following gives the average variation 

 in size in different animals, the largest being in Siren lacertina, 

 and the smallest in Moschus Javanicus : 



Musk deer, T T<JOO f an mcn m diameter; goat, ^,00; red 

 deer, TT ?oo; horse, T 1 <j : sheep, ^^\ cat, TT Vo ; rabbit, 3^; 

 ox > Wuo: man, ^Vo: dog, ST Vo: ape, 3 Voo: elephant, .j,Vu; 

 eel, 18 Vo; frog, TorVo: salamander, r i- -; proteus, T / H) . 



3. Effects of reagents. When specimens of fresh blood are 

 examined with the microscope the red corpuscles show a 

 tendency to adhere by their flat surfaces so as to form longer 

 or shorter chains or rolls, like rolls of coin. As this is not 

 seen in the vessels during circulation, it is probably due to 

 some unknown change. Almost every microscopic specimen 

 of blood contains also red corpuscles, which present the form 

 known as crenate. This is a stellate, or jagged and uneven 

 form, as if a number of minute granules or points projected 

 from the surface of the corpuscle, which changes from a dis- 

 coid to a globular form. This crenate form is known also as 

 mulberry shape, horse-chestnut shape, rosette and thorn-apple 

 forms, etc. Under high powers the projections are readily 

 seen. Whether due to external agencies or the vital power 

 of the blood is unknown. Water, acid, alcohol, electricity, 

 and many other reagents, produce discoloration of the red 

 globules, the haemo globin becoming dissolved in the plasma. 

 What is left of the corpuscles is called the stroma. The re- 



