40 FORM, SIZE, AND NUMBER OF ERYTHROCYTES IN ANIMALS. 



from the margin of a cover-glass permits the process of dissolution to be readily 

 observed microscopically. At first the corpuscles abruptly become globular in 

 jerks and thus apparently smaller; later they swell up like soap-bubbles. 



The influence of the gaseous content of the red blood-corpuscles upon their 

 solubility is remarkable. The corpuscles in blood containing much carbon dioxid 

 are dissolved most readily; those in blood containing much oxygen are much less 

 readily dissolved; while between the two are the corpuscles containing much 

 carbon monoxid. Total removal of the gases of the blood causes of itself the devel- 

 opment of a lake-color. 



The erythrocytes possess a certain degree of resistance to the action 

 of solvents. 



The following method may be employed to determine this degree readily. A 

 drop of blood is mixed with an equal amount of a 3 per cent, solution of sodium 

 chlorid, and then as much distilled water is added as is required to dissolve all of 

 the red blood-corpuscles. The method is carried out as follows with human 

 blood: With the aid of the blood-mixer of the blood-corpuscle counting-apparatus 

 (Fig. 3) blood is collected from a puncture of the skin up to the mark i, and is 

 expelled for microscopic examination into a concave glass cell, in which previously 

 an equal amount of a 3 per cent, solution of sodium chlorid had been placed. 

 Well admixed, all of the erythrocytes will be preserved. Now, by means of the 

 same apparatus, distilled water is added, and the changes observed under the 

 microscope until all of the red corpuscles are dissolved. The glass cell is covered 

 after each addition in order to prevent evaporation. The erythrocytes of some 

 persons are more readily dissolved than is normal, being soft and plastic and under- 

 going striking changes. In addition, reference may be made to the following 

 states: All blood-mixtures that jeopardize the normal condition of the erythro- 

 cytes, such as cholemia, intoxications with substances that cause dissolution of 

 the blood-corpuscles and high grades of venosity. Interesting observations may 

 be made further in the presence of blood-diatheses and infectious processes, hemo- 

 globinuria, and burns. The resistance appears diminished in case of anemia and 

 of fever. 



FORM, SIZE, AND NUMBER OF ERYTHROCYTES IN 

 DIFFERENT ANIMALS. 



All mammals, with the exception of the camel, the llama, the alpaca, 

 and related animals, as well as the cyclostomata among fish, for instance 

 the lamprey, have coin-shaped circular erythrocytes. The mammalia 

 excepted have oval erythrocytes without nuclei, while birds, reptiles, 

 amphibia (i, B) and fish, with the exception of the cyclostomata, have 

 similarly shaped erythrocytes with nuclei. 



Size M = o.ooi Millimeter. 



Coin-shaped Oval Blood-corpuscles. 



Blood-corpuscles. Short Diameter. Long Diameter. 



Elephant, 9.4 // Llama, 4.2 // 7.5 /u 



Man, 7.5 



Dog, 7.2 



Rabbit, 7.16 



Cat, 6.2 



Sheep , 5.0 



Goat, 4-25 

 Musk-deer, 2.5 



Pigeon, 6.5 " 14.7 



Frog, 16.3 " 23.0 ' 



Triton, 19.5 " 29.3 ' 



Proteus, 35.6 " 58.2 ' 



The corpuscles of the amphiuma are about a 

 third larger than those of proteus. 



Among vertebrates, the blood of the amphioxus is colorless. The large blood- 

 corpuscles of many amphibia can be seen with the naked eye. In those of the 

 frog a nucleolus is demonstrable. It is readily explicable that the larger the 

 blood-corpuscles the smaller must be their number and their total superficies in 

 a given volume of blood. Only in birds is the number relatively larger than in 

 other classes of vertebrates, notwithstanding the greater size of the corpuscles. 

 This probably depends upon the fact that in them metabolism exhibits the 

 greatest energy. Among mammals carnivcra have a larger number of blood- 



