LESSON 23.] CELLS FLOATING IN ANIMAL FLUID. 69 



in Fig. 101. This illustration has been magnified with an 

 eighth object glass, to give greater size and distinctness to the figure. 

 The nuclei (a) will be clearly seen within the cells, and the fibres 

 of fibrine range from four to seven in number ; in every instance they 

 can be seen to be pulled out, as it were, from the nuclei. This has 

 been seen before by Prof. Owen, but misinterpreted (if the above 

 facts be true) ; the Professor believed that the lines indicated a puck- 

 ering of the cell-wall. 



391. If these observations can be depended on, and they require 

 confirmation by another experimenter, there seems to be great 

 reason to believe that the human corpuscle contains a nucleus, and 

 that its element is chiefly fibrine. That the fibres of fibrine, in the 

 experiments alluded to, really arose from the nuclei, and not from 

 the colorless corpuscles, is rendered certain by the fact that all that 

 remains of them retains the red color distinctly ; the nuclei, as will 

 be seen by reference to the figure, are of all sizes some moderately 

 large, others quite minute. 



About an hour after a mosquito ha'd made a meal, it was killed, 

 and the human blood contained in its crop and stomach examined by 

 the microscope. The nuclei (real or apparent) had disappeared, 

 leaving only a faint ring (Fig. 102) to mark its place. 



Another mosquito was FI<J m 



killed three or four hours after 

 a meal; in this instance, nei- 

 ther nuclei nor rings could be 

 discovered (Fig. 103) ; but in 

 both instances the corpuscles 

 retained their full s i Z e_ a ppa- H ^ mbloodw ^ cle8 ' from8tomMhofMos< l uito - 

 rently uninjured by the action of the digestive process. These ex- 

 periments were repeated several times, with the same uniform results, 

 and the preparations exist to confirm the accuracy of the experiments. 



The inference appears to be that the human blood corpuscle does 

 contain a nucleus ; that its structure differs from that of the cell- 

 wall, and that it is far more accessible to the action of the saliva and 

 the gastric juice than the latter, which remains intact long after the 

 former has disappeared. 



392. The shape of the human blood corpuscle is discoidal ; so too 

 in the mammalia ; in the birds, reptiles, and fishes, it attains much 

 greater size, and is more or less oval or oblong in shape, as may be 

 seen in the blood of the common fowl (Fig. 104). It has been said 

 that the ostrich possesses the largest red corpuscle of all the warm- 



