HARDWICKE'S SCIENCE-GOSSIP. 



pupa has hardened before it has been noticed, it 

 remains perfectly safe. Here, I know some of my 

 readers will say, " How could they get at them when 

 they are enclosed in a strong web ? " Eut numbers 

 of mine changed amongst their food on the floor, con- 

 trary to their usual habit ; but if a weak place appeared 

 in those that did spin a web. it was quickly attacked 

 by several of the larva:, and an inroad soon made. 

 The following trait is also interesting, as bearing on 

 their sense of smell. I found when I gathered fresh 

 food for the larvae in the early part of the morn- 

 ing, and placed it ia their compartment, that they 

 flocked eagerly towards it, leaving their stale food, on 

 which most of them were feeding before. But if I 

 fed them later in the day, the majority of them stayed 

 on the stale food, although the fresh food was re- 

 peatedly placed in close proximity to them. It may 

 be that the dew has something to do with this by 

 drawing out the scent of the plants, especially as I 

 fed them mostly on Mentha (principally rotundi- 

 folium), horse-raddish, and comfrey. 



July 1st. The imagos appeared and I found that 

 I had a number of very fine specimens. By mishap 

 I allowed several to remain in the cage, which was 

 put away in an old cupboard. Going to the cup- 

 board, nearly five weeks after, I found that one was 

 still alive, but the other four had succumbed — and 

 remember, there had been no food in the cage during 

 this period, nothing but the layer of soil on the 

 bottom. How the one lived I cannot imagine. On 

 the gauze at the top, I found ova had been deposited 

 in a considerable quantity, and further — that they 

 emerged in a few days after. The small larvae were 

 not undersized or weakly either, as one would expect 

 from the treatment the imagos received, ' but were 

 rather over the ordinary size at this period. I send 

 specimens to the Editor of the larvae at one day old. 

 The influence of light on their development I tested 

 in the following way. I enclosed the young larvae 

 with the food-plant in a dark box, with holes for the 

 free admission of air, and stored it in a " dark room " 

 used for photography. They were kept well supplied 

 with food. The development of each stage was con- 

 siderably retarded, so that specimens in the, last stage 

 (I cannot call them imagos) were not obtainable till 

 the September following. Not one, however had its 

 wings fully developed, some barely the eighth of an 

 inch in length. The longest was half an inch, and I 

 believe, if growth had continued, the wings would 

 have been entirely dark brown. For this experiment 

 I selected strong, healthy-looking caterpillars, so that 

 it is all the more conclusive as to the bad effects of 

 darkness on their perfect development. The influ- 

 ence of heat on the wing at the time of expansion is 

 also, it would appear, decidedly bad, drying up the 

 juices as fast as they can be formed, till the wing is 

 made dry and brittle, and incapable of attaining its 

 full size. I reared some over a hot mantel-shelf; 

 few of these but whose wings did not present the 



appearance of shrivelled deformity. The great 

 strength in a few cases had endowed several for this 

 struggle for existence, it is true, but they were cer- 

 tainly not perfect specimens. Most Lepidoptera you 

 will thus find emerge from their chrysalis in the cool 

 of the evening, so as to escape the hot sun and dry 

 air. Those I kept emerged about eight or nine in the 

 evening or during the earliest hours of the morning. 

 A red liquid, acid substance is found plentifully 

 sprinkled about the cage after such emergences, and 

 is used in softening the hard, dry case, so that it can 

 easily be parted by the moth, and a passage made 

 when it wishes to appear. In one case only did the 

 pupa case remain attached to the imago's body ; it 

 did not, however, survive, but died shortly after 

 emergence. 



THE HUMAN BLOOD-WORM {FILARIA 

 SANGUINIS HOMINIS). 



IT has been suggested to me that I might bring 

 together in a note the materials I have collected 

 regarding the Filariae found in human blood ; and 

 the more so as circumstances have admitted of my 

 obtaining several living specimens of the parasite, 

 from some of which my sketches have been made. 

 So far as I have been able to ascertain, the subject 

 has not been illustrated in Science-Gossip ; my 

 note may, therefore, serve to fill a vacant place. 



In 1870 Dr. T. R. Lewis, formerly of Calcutta, 

 and since deceased, found nematoid worms in 

 chylous urine. In the beginning of 1S72, whilst 

 examining the blood of a native of India — a patient 

 in the Calcutta Medical College Hospital — who was 

 suffering from diarrhoea, Dr. Lewis observed no less 

 than nine minute active worms on a single slide, and 

 identified them with the Nematoids previously ob- 

 tained by him in cases of chyluria. From this time 

 onwards he paid considerable attention to the 

 subject ; and he sent a slide containing some speci- 

 mens of the worm to Professor Parkes, at Netley, 

 who showed them to Mr. Busk. The name Filaritz 

 sanguinis hominis appears to have been then con- 

 ferred on this organism. During the course of the 

 two following years Dr. Lewis continued his investi- 

 gations, with the result that he traced Filariae directly 

 to the blood in ten, and detected them in various 

 tissues and secretions in at least thirty cases ; the 

 parasites were always associated with chyluria, 

 elephantiasis, or some closely allied pathological 

 condition. In one case (of chyluria) the patient had 

 been [a leper for fourteen years : several slides con- 

 taining active Filariae were obtained from his fingers 

 and toes. . 



Dr. Cooke in his instructive and popular little 

 book on " Ponds and Ditchesi" appears to suggest 

 that Filariae are pathogenetically associated with 

 leprosy, a view which scarcely derives support from 



