12 ELEMENTS OF HISTOLOGY. [Chap. n. 



become smaller and spherical, but beset all over their 



surface with minute processes. This shape is called the 



horse-chestnut shape (Fig. 8, b, c). It is pro- 



O O bably due to the corpuscles losing carbonic 



acid, as its addition brings back their discoid 



shape and smooth circular outline. On ab- 



^ Tp stracting the carbonic acid they return to 



& the horse-chestnut shape. Water, acid, 



Pl fcd~ H Biood alcohol, ether, the electric current, and 



a owtutto-T man y other reagents, produce discoloration 

 of the red blood corpuscles ; the coloured 

 matter generally the combination of 



the blood-colouring matter with globulin known as 



hcemoglobin becoming dissolved in the plasma. 



What is left of the corpuscles is called the 



stroma. In newts' and frogs' blood a separation of 



the stroma from the 



nucleus and haemoglobin Q 



can be effected by means a 



of boracic acid (Fig. 9, B) ; 



the former is called by 



Brucke the OEkoid, the 



, r, . , mi . Fig. 9. Bed Blood Corpuscles of 



latter Zooid. This stroma Man and Newt. 



Contains amongst Other A, Human red corpuscles after the action 



, i of tannic acid : a, three red corpuscles, 



things milCh para- from which the haemoglobin is passing 



i 1 i m , out; 6, Roberts's corpuscles. 



globulin. The Stroma B, Newt's red corpuscles after the action 



T* .1 i /. of boracic acid: a, a corpuscle showing 



Of the COrpUSCleS OI Bruckes' zooid and oikoid ; &,acorpus- 



, ., . A . cle showing the reticulated stroma; 



amphibians IS Seen, c, a corpuscle showing the reticulum 



\ , . in the nucleus ; d, the nucleus passing 



under certain reagents, out. 

 to be of a reticulated 



structure, but in the fresh state appears homo- 

 geneous and pale. Discoloration of the blood cor- 

 puscles can also be observed to take place in blood 

 without the addition of any reagents or with that of 

 indifferent fluids, such as the aqueous humour of the 

 eye, hydrocele fluid, etc. The number of corpuscles 

 undergoing discoloration is, however, small. 



