CORPUSCLES. 



animal: the goat was long supposed to have the smallest, viz., about 

 of an inch ; but Mr. Gulliver has found that they are much smaller in the 

 Meminna and Napu musk-deer, in which animals they are less than ju^^th 

 of an inch. In birds they do not vary in size so much ; from Mr. Gulliver's 

 very elaborate tables of measurement it appears that they range in length from 

 about yy'o-oth to Y^Vo^ ^ an i ucu ne states that their breadth is usually 

 a little more than half the length, and their thickness about a third of the 

 breadth or rather more. He found a remarkable exception in the cor- 

 puscles of the snowy owl, which measure ^--^ n th of an inch in length ; and 

 are only about a third of this in breadth. In scaly reptiles they are from 

 j-^^th to y^ 1 ,} o^k f an i nca * n length ; in the naked amphibia they are 

 much larger : thus, in the frog they are -jo'Vo-th f an i ncn l n g an( i TToo^k 

 broad ; in the salamander they are larger still ; but the largest yet known in 

 any animal are those of the proteus, which are -j^th of an inch in length, 

 and T ^ T th in breadth ; the siren, which is so much allied to the proteus in 

 other respects, agrees with it also in the very large size of its blood- 

 corpuscles ; they measure -j-^th of an inch in length, and -yg-oth in breadth. 

 In the skate and shark tribe the corpuscles resemble those of the frog, in 

 other fishes they are smaller. 



From what has been stated, it will be seen that the size of the blood-cor- 

 puscles in animals generally is not proportionate to the size of the body ; at 

 the same time Mr. Gulliver remarks, that " if we compare the measure- 

 ments made from a great number of different species of the same order, it 

 will be found that there is a closer connection between the size of the 

 animal and that of its blood-corpuscles than has been generally supposed ; " 

 and he has pointed out at least one example of a very natural group of 

 quadrupeds, the ruminants, in which there is a gradation of the size of the 

 corpuscles in relation to that of the body. 



C. Schmidt, on account of the varying size which the corpuscles 

 present, in dependence upon the density of the liquor sanguinis, has sub- 

 jected them to repeated measurements when dried, in a very thin layer upon 

 slips of glass. It has been thus found that from 95 to 98 per cent, present 

 the same magnitude. 



Structure. The large corpuscles of the frog and salamander, when drawn 

 from the vessels and placed under the microscope, appear to consist of a thin, 

 transparent, vesicular envelope, enclosing a solid oval nucleus in the centre, 

 with a quantity of softer red-coloured matter disposed round the nucleus and 

 filling up the space between it and the envelope. When exposed to the 

 action of weak acetic acid, (fig. xvi., 3 ) the colouring matter is speedily 

 extracted, and the nucleus becomes distinct, whilst the envelope is rendered 

 so faint as to be scarcely visible ; but its outline may be still brought 

 into view by adding solution of iodine, which gives it colour and opacity. 

 Pure water extracts the colour and distends the corpuscle by imbibition, 

 altering its shape from oval to round, and making the nucleus more 

 conspicuous. Often in these circumstances the nucleus is displaced from its 

 central position, and it may even be extruded altogether, as if by bursting 

 of the corpuscle, which then appears flattened and colourless, and in this con- 

 dition is generally supposed to represent only the ruptured and empty 

 envelope ; but even with the help of iodine, no rent can be perceived in it. 

 For this and also for other reasons some think that what remains behind 

 after escape of the nucleus is really the soft and now colourless substance of 

 the corpuscle, and that it has no distinct envelope. On the opposite view it 

 is suggested that the absence of apparent laceration in the envelope is owing 



