15fi 



KNOWLEDGE. 



May, 1915. 



the Sinai Peninsula. " K very hand is against it during the 

 entire year, and its freshly dropped kids are eagerly hunted 

 by the natives with dogs." Its numbers are dwindling, 

 but it still persists. Caves among the rocks are used as 

 hiding-places. It seems to be independent of water — at 

 least during winter and spring. 



LONG -CONTINUED PARTHENOGENESIS. — Dr. 

 A. M. Banta, working at the Cold Spring Harbour for 

 Experimental Evolution, has reared a hundred partheno- 

 genetic generations of Daphnia pulex, the common water- 

 flea. There was no occurrence of males, and no evidence 

 of decreased vigour or loss of vitality in the lines. Hence 

 it appears that there is no necessary sexual cycle in the 

 reproduction of this crustacean. 



A POWERFUL TOXIN.— A mould growing on bread 

 does not suggest an extreme of poisonousness, but that is 

 what R. A. Gortner and A. F. Blakeslee have found to be 

 true of Rhizopus nigricans, which produces a deadly toxin. 

 The toxin has no effect when taken into the food canal 

 by a rabbit, but it is fatal if injected into the veins, even in 

 so small an amount as 1 to 275,000 parts of body weight. 

 It is one of the most poisonous organic substances known. 



GASTROLITH FROM A MOOSE.— It is not uncommon 

 to find concretions in the stomach of herbivorous animals, 

 the " hair-balls " of horses and cows being very well known. 

 Professor D. Fraser Harris describes an interesting form 

 from the Moose, which consisted of concentric layers of 

 calcium phosphate around a flat, smooth piece of slate. 

 The whole was a hard oval calculus, about two inches in 

 length. Similar concretions have been reported with a 

 tooth in the centre. 



PREDICTION OF SEX.— It would be difficult to find 

 a problem in regard to which there has been, and still is, 

 quainter speculation than that of the determination of 

 sex. There is a widespread theory in Japan that the dis- 

 position of the hairs on an infant's neck affords a basis for 

 predicting the sex of the next child, if there is one. If the 

 lines of hairs from the neck to the occipital region are 

 divergent, the next child will be a boy ; if the lines converge, 

 a girl. Mawe and Perriraz have been recently inquiring 

 whether this holds for Europe. 



A ZOOLOGIST AT THE FRONT.— Corporal Fred Vies, a 

 zoologist well known for his interest in the problems of animal 

 locomotion and for his beautiful cinematograph films of 

 sea-urchin development, made an interesting observation 

 on a road somewhere near the Aisne. He was bicycling 

 slowly on a day without wind, and observed a wasp flying 

 backwards in front of him. That is to say, the tip of the 

 abdomen was foremost in the progression, and the head faced 

 the observer. The wasp was attracted by traces of fruit 

 on M. Yles's cap, and kept up the backward flight for more 

 than ten yards at a time. As the observer points out, the 

 case well deserves further investigation. 



NUMBER OF BRITISH BIRDS.— The British Ornitho- 

 logists' Union has brought out a second and revised edition 

 of their well-known " List of British Birds." It includes 

 no fewer than 475 names. 99 more than there were in the 

 first edition (1883). An appendix gives a long list of birds, 

 whose claims to be called British have been rejected by the 

 Editorial Committee. Of the authenticated list of 475, 

 18S are regular breeding birds, 286 are non-breeding, and 

 one (the Great Auk) is extinct. There are 141 residents, 

 47 summer visitors, 46 winter visitors, 30 birds of passage, 

 61 occasional visitors (recorded more than twenty times), 

 and 149 rare visitors (recorded on fewer than twenty occa- 

 sions). That the last should be the largest category in the 

 classification shows how diligent the search for the occurrence 

 of rare birds has been in the British Islands. 



DETERMINATION OF SEX IN PIGEONS.— Very 

 interesting observations have been made by Dr. Oscar 

 Riddle, who finds evidence of two different kinds of eggs in 



pigeons. Those destined to produce males are smaller, 

 and have higher water-content and smaller energy-content 

 than those that will produce females, By means of the 

 bomb calorimeter he has been able to demonstrate that eggs 

 destined to become males contain less stored energy than 

 eggs destined to develop into females. We are referring to 

 a preliminary notice of Dr. Kiddle's work, and we presume 

 that the account of his observations will explain how it is 

 known that an egg is destined to become a male or a female 

 until it docs. We note however, that the investigator is 

 quite clear that tin- difference in energy-content may be 

 an effect of sex-determination, and not the cause. 



BLIND TACTICS. — How can one explain the well- 

 known fact that many an insect-mother is careful to secure 

 the welfare of her offspring which she never sees ? She 

 lays her eggs in appropriate places, often very difficult to 

 get at ; she surrounds them with food-materials ; she often 

 collects a living larder of paralysed creatures to satisfy 

 their juvenile appetite. Vet she is dead and gone before 

 her offspring are hatched ! There is no doubt that we have 

 here to deal with one of the greater problems of biology, 

 and one that has not been seriously tackled. How can 

 a creature work sedulously, intricately, persistently towards 

 an end which is unknown, which cannot be pictured, because 

 never experienced ? We would, in the meantime, suggest 

 that part of the puzzle may disappear if we assume that the 

 ancestors of the insects in question did survive to see their 

 offspring. It may be that the routine now instinctive. — 

 that is to say, hereditarily entailed — was established among 

 ancestral forms that did survive to see the reward of their 

 labours. The dim meaningfulness of to-day may be an 

 echo of a clearer significance in ages long since past. 



LONG PEDIGREE OF SLIPPER ANIMALCULES 

 MULTIPLYING ASEXUALLY.— We have already re- 

 ferred in these Notes to the continuous generations of 

 Paramecium aurelia which have been observed in the Yale 

 Zoological Laboratory by Professor L. L. Woodruff. In 

 November, 1914, the race had existed for seven years and 

 four thousand five hundred generations, and remained 

 quite normal, though there is no conjugation. In a study by 

 Woodruff and Rhoda Erdmann attention is directed to 

 a very interesting occurrence which they call "endomixis." 

 At frequent intervals the old nuclear apparatus breaks down, 

 as if conjugation were going to occur, and a reorganisation 

 is effected, which initiates a period of new metabolic activity, 

 and therefore of reproductive activity. It occurs on an 

 average about once a month. It may afford a field for the 

 origin of variations. It is an internal regulatory pheno- 

 menon which is self-sufficient for the indefinite life of the 

 race in a favourable environment. This is obviously an 

 idea of great interest. 



MEMORY OF COCKROACH.— Dr. F. Bretschneider 

 kept Cockroaches in a breeding-cage, and fed them in 

 an adjoining experimental cage, the communication between 

 the two being through an aperture which could be closed. 

 The feeding-cage had a glass floor, which was cleaned every 

 day, and the cage was divided into two chambers by a 

 partition with six apertures, which could be closed and 

 opened. The food was placed in the chambers farthest 

 from the dwelling-cage. A lateral opening in the partition- 

 wall was opened to begin with, and the insects got accus- 

 tomed to use it. After a time it was closed, and one at the 

 other side was opened. But the insects continued to try 

 the closed door, which shows a local memory. There could 

 be no scent, as the glass floor was washed every day. 

 Szymanski showed in 1912 that Cockroaches could be taught 

 to prefer the light half of a cage to the dark half, which is 

 contrary to their nature, by arranging that those who went 

 into the dark half got a mild electric shock. They soon 

 learnt and soon forgot again, but they took a shorter time 

 to learn the second time. The seat of memo r ' is almost 

 certainly in the mushroom-shaped bodies on i anterior 

 surface of the protocerebrum. 



