HARD WICKE S S CIENCE- G O SSI P. 



mens, male as well as female, of this obscure creature 

 fell to my lot during the summer of 1889, from 

 Wanstead Park, Essex. Mr. D. Bryce had met with 

 female examples a year earlier, and has since come 

 across solitary individuals on several occasions and 

 from different localities. My present purpose is 

 merely to call the attention of other workers to the 

 fact of the occurrence of this species in districts near 

 London. The specimens seen by Mr. Bryce appear 

 to differ in certain structural details from those which 

 I myself examined ; and as this discrepancy, if 

 proved to "be actual and constant, may affect the 

 now-accepted name of the species in a manner which 

 I cannot here discuss, it is advisable to defer any 

 description of this form until the acquisition of 

 further specimens shall have made us more familiar 

 with its anatomy. 



WOODLAND WANDERERS, OR THE 

 MYCETOZOA. 



No. II. 



[Continued from p. 251.] 



SENSITIVE creatures are these plasmodia ; 

 requiring special environment to enable them 

 to flourish. Moisture is essential, with a temperature 

 not too low. Frost apparently drives them into 

 hiding, whilst too much dry heat desiccates the 

 surface of the matrix, and thus compels them to seek 

 sustenance in the moist interior of the decayed vegeta- 

 tion. This may be rotten wood or decaying leaves, 

 but in any case it must be organic. None of them 

 contain chlorophyll, and hence have not the power to 

 assimilate food from the inorganic substances of the 

 earth, or the impalpable forces of the light and air. 

 There are cases on record in which the sporangia, or 

 f ruiting heads, have been found on lead pipes and old 

 shoes, but these do not imply that they fed on such 

 intractable articles, but that having previously 

 absorbed sufficient nutriment, it is a matter of 

 indifference to what materials they may creep 

 in order to form their capsules. The plasmodium 

 stage is essentially the feeding one, and during this 

 period the protoplasmic contents are particularly rich 

 in formative materials. One may even suggest that 

 there is a distant analogy between this life-period of 

 the organism and the larval stage of the Lepidoptera. 

 The plasmodia, having no protective cell-covering, are 

 peculiarly sensitive to injury by contact. It is really 

 wall-less protoplasm, and hence the slightest touch 

 from the incautious finger causes local death, 

 although the other portions may remain healthy. 

 The fact that its contents are not restricted by 

 cell-walls may account for their excessive mobility, 

 enabling them to insinuate themselves into the 

 interstices of wood, that may be only in an incipient 

 stage of decay, and also into the honeycomb-like 



7 



cavities of the fungi (Irpex) on which they often occur. 

 Their^course over these fungi is always indicated by 

 a marked change in them ; their normal hue is a 

 creamy white, but when plasmodium has passed over 

 them they change to a dirty drab, and are apparently 

 in a moribund condition. The discoloration of the 

 food-plant may also be partly due to a slimy 

 substance which is left by the Mycetozoon as it 

 shifts its position, as though it threw off the waste 

 material that would otherwise accumulate in its own 

 substance. This rejection of useless contents is 

 particularly marked in the fruiting stage. 



Although so singularly sensitive to contact, it will 

 endure strange vicissitudes without injury. It may 

 be dried up, till it is apparently hard and tough,* in 

 which condition it may be kept for an indefinite 

 period — weeks and even months — after which, by the 

 application of moisture, with careful treatment, it 

 may be resuscitated and it will become as active as 

 ever. During the closing part of the summer of the 

 past year we were desirous to obtain some 

 plasmodium, but were unable to do so owing to the 

 dryness of the season. A request for some of it was 

 sent to an esteemed correspondent, who is a specialist 

 in this department of science. In reply, a small 

 portion of desiccated plasmodium attached to a 

 fungus was forwarded in a pill-box. This had been 

 dried artificially several weeks previously. Wishing 

 to see if it would revive, it was placed in a shallow 

 glazed vessel four or five inches wide. On the 

 opposite side of the vessel a portion of a suitable 

 fungus was placed, and the intermediate space was 

 filled with fragments of decayed wood. The whole 

 was then immersed in water, or rather water was 

 poured over until the contents of the dish were covered. 

 It was noticed that after two or three days the 

 plasmodium had imbibed sufficient moisture to 

 enable it to become partly detached from its position. 

 In about a week it threw out a vein-like process, 

 which traversed the intervening space over the 

 fragments of wood, and reached the fungus on the 

 opposite side of the vessel. In a few more days the 

 whole creature had left its original position and had 

 transferred itself to the fresh food which lay within 

 its vicinity, although several inches distant. By 

 what occult power it could direct its course in the 

 desired direction, and that after weeks of. apparent 

 suspension of animation, is beyond the comprehension 

 of the present observer. 



In addition to the movements of the whole mass, 

 or certain portions of it, in search of sustenance, 

 which changes of position may be noted by the naked 

 eye, or better still by a pocket lens, there is also a 

 circulation of the protoplasmic contents. It can, 

 however, scarcely be called circulation in the 

 ordinary sense of the term, as the course is not 

 always in one direction. There is an ebb and flow 



* Technically termed scleroi.ium. 



