1887] Psychology. ? 683 
as such, are wanting in human blood, but since we have had our 
attention directed by Hayem to the fact that the “ hamatoblasts” 
play an important part in the coagulation of the frog’s blood, it 
is possible to think that some element is present in mammalian 
blood which also acts as a factor in coagulation, The coagula- 
tion of the frog's blood begins with the grouping of the “ hama- 
toblasts” into-a rosette form. ` The red corpuscles then arrange 
themselves radially about this point as a centre. o we find an 
analogous process at the commencement of the coagulation of 
mammalian blood? The blood of mammals coagulates very rap- 
idly, whereas that of the frog changes very slowly; hence, if we 
would study the blood of mammals before coagulation, we must 
prevent this process by means of some reagent. Such an ex- 
periment cannot be tried with a human being, but is easily made 
with a dog. The reagent usually employed is peptone, which 
is injected in solution into the jugular vein of the dog, the 
amount injected being 0.3 grain peptone for every kilogramme 
weight of the dog. The microscopical examination of blood 
in which coagulation has thus been prevented shows that there 
exist in the blood, aside from the other elements, tiny tablet- 
like granules which tend to cling together in clumps. These 
_ Not only the possibility to distinguish the different elements of 
the blood, but through it, it has been possible to discover ele- 
ments which, like the “hamatoblasts,” accompany the phe- - 
nomenon of coagulation, and also to’ determine in part the rela- 
tion that exists between the elements. It would flot agree with 
‘the general plan of nature if every form did not play a different 
‘Tole in the organism, and after all that has been discovered it is 
not improbable that we shall one day be able, through watching 
: the changes which the different elements undergo in the blood, 
to discover the disturbances caused by different ferments and 
Organisms in the blood. Thus we think that the hope of clever 
_ Physicians may one day be verified, that the analysis of a drop 
Of blood may give a clue to the pathological changes in the 
‘Dody.— Alice Leonard Gaule. 
shi. ‘PSYCHOLOGY. | 
os Intelligence of Echinoderms.—The experiments of Professor 
Be -Preyer upon starfish and ophiurids tend to prove that they are 
Mel 
