( 167 ) 

 PEOGRESS OF MICEOSCOPICAL SCIENCE. 



The Animal Distribution of Hcemoglohin. — This is a subject of 

 some importance, especially when viewed from Mr. Sorby's aspect. 

 However, M. Quinquancl, who has investigated its distribution through 

 the animal kingdom, has not, wo believe, made any inquiries in this 

 direction, though he has published tables of its distribution in 

 animals. His conclusions are thus formulated: — 1. The progressive 

 diminution of the quantity of hfemoglobin contained in the same 

 volume of blood follows, in general, the degrees of the animal scale ; 

 but the blood of Primates does not contain most. 2. The blood of 

 young animals contains less haemoglobin than that of adults. In 

 many species the placental blood contains as much as that in the 

 general circulation. In old age the quantity diminishes. The curve 

 of variation presents a slight fall at first, corresponding to the first 

 days of extra-uterine life ; then it rises gradually (in the case of man) 

 to twenty-five years, and continues horizontal till fifty ; after which it 

 slowly falls again. 3. The proportion of haemoglobin in birds is 

 much smaller than in mammalia. The weight of the corpuscles is 

 slightly greater in birds, but the corpuscles of mammalia contain three 

 times less albuminous matter. 4. The influence of sex is observable. 

 Females have generally less haemoglobin than males. 5. The lymph 

 of Crustacea contains four to five cubic centimetres per cent., while 

 ordinary water contains, at its maximum of saturation in winter, one 

 cubic centimetre per cent., and in summer only six-tenths of a cubic 

 centimetre. 



The Emhryology of Limulus was detailed by Dr. L. S. Packard, at 

 the meeting of the American Association. He said that in a recent 

 paper on the Embryology of Limulus, published in the Memoirs of the 

 Boston Society of Natural History, he stated that the blastodermic 

 skin just before being moulted consisted of nucleated cells ; and also 

 traced its homology into the so-called amnion of insects. This summer 

 he has, by making transverse sections of the egg, been able to observe 

 in a still more satisfactory manner these blastodermic cells and observe 

 their nuclei before they become effaced during or after the blasto- 

 dermic moult. On June 17 (the eggs having been laid May 27) the 

 peripheral blastodermic cells began to harden, and the outer layer — 

 that destined to form the amnion — to peel off from the primitive band 

 beneath. The moult is accomplished by the flattened cells of the 

 blastodermic skin hardening and peeling off from those beneath ; 

 during this process the cells in this outer layer losing their nuclei, 

 and, as it were, drying up, contracting and hardening during the 

 process. This blastodermic moult is comparable with that of Apus, 

 as he has already observed, the cells of the blastodermic skin in that 

 animal being nucleated. The paper set forth that while the process 

 above described resembled features in the development of the scorpion, 

 and thus strengthened the sui-»j)osition of Burmeister, that the Limulus 

 is related to the spiders, nevertheless other features which Prof. 



