1884.] 
On Animal Chlorophyll. 
93 
It need scarcely be said that, if such is universally and 
exclusively the nature of the chlorophyll observed within 
which an, ■ ™ ’ ‘ is the Sreat and certain feature by 
other Th?' and plants are distinguished from each 
generalisation, cannot, however, as yet claim 
our acceptance, since Herr T. W. Engelmann (“ Pflii^er’s 
which V ’ tn 1 ' Phy , S 1 loIo S ie ”) has published certain observations 
’ • say the least, must render the above-mentioned 
assumption very questionable. 
ySar ! a S° Engelmann met with Vorticella; whose 
tissues did not contain distindt granules of chlorophyll, but 
fmbi hed d M C lffU 1 Se f, ho A m °^ ene ous green colour as if from 
anhnnl ^ loro P hylL As at tba * time the occurrence of 
animal chlorophyll was not questioned, he paid no further 
attention to these animalcules. Now, since the closer 
investigation of this colouring-matter has become of capital 
importance, he returned to the subjeft. He met with the 
necessary specimens only after long search, and in small 
umbei s. He found upon Vauclierice, both living and dead, 
along with numerous colourless specimens of Vorticella 
campanula and V. nehulifera, a few Vorticella of a diffused 
green colour. In addition to their colour, these were dis- 
tmguishable by the closer and more delicate annulation of 
, eu bod J5 s ’ and b y a greater transparence of their endo- 
h'xx ^ " t S reen colouration was strictly limited to the 
ectoplasm. In recent specimens the colour was quite homo- 
geneous. It was deepest in the so-called cuticle, and was 
wanting on the surface of the peristomal disc. The entire 
endoplasm and the long nucleus seemed to contain not a 
trace of chlorophyll. In different specimens, however, both 
re in ensi y and the distribution of the colour were found 
to vary. 
The important question whether living chlorophyll— or 
at any rate a genuine, assimilating chlorophyll— was present 
was investigated by Engelmann by means of the so-called 
adtena-method.^ He added a small quantity of a liquid 
con taming bacfteria to a drop which contained a bright green 
v orticella attached to a dead branch of Vaucheria. " The 
latter was free from chlorophyll. The preparation was 
p aced in the dark box” of the microscope, and the 
Vorticella, by means of a suitable arrangement, was 
illuminated by a specTrum. After about a quarter of an 
oui a distindt accumulation of movable badteria was seen 
round the Vorticella, whilst previously none or but few had 
been seen. 
Without doubt these Vorticellae possess the property, by 
