Notes and Memoranda. 225 



NOTES AND MEMOEANDA. 



Germs of Infusoria. — M. le Vicomte Gaston d'Auvray has addressed a let- 

 ter to the French Academy, stating that hy means of an apparatus, which he calls 

 a dialyser, he filters water or other liquid so as to separate and collect the germs 

 of Infusoria. He finds two sorts of germs, greenish grey and pearly white. He 

 says they exist in all water, even when distilled, although most plentiful in that 

 which is impure. In air he also finds them, and they abounded in the thick fog of 

 2nd of December, 1863. All the grey germs are spherical, varying in diameter 

 from mm .00024 and mm ,0Q034. The pearl white corpuscles are of three sorts : 

 A and B spherical, their diameter being mm ,00040 and O mm ,00065 ; C are ovoid, 

 with lesser axis, mm ,00065, and major axis mm ,00080. The grey corpuscles he 

 calls germs of protophytes ; the white, of animalcules, among which he includes 

 vibrions. If the corpuscles are all removed from water, but the debris of organic 

 matter, such as bits of textile fabrics, vegetable epiderm, pollen grains, butterfly 

 scales, smoke particles, allowed to remain in a flask which is sealed hermetically, 

 no life is developed, and the result is negative if some white of the white corpus- 

 cles are added. If however some of the greenish grey corpuscles are added, first 

 protophytes, then amoeba?, monads, and vibrions appear. If into these flasks con- 

 taining the grey corpuscles, the white ones, A, B, and C are added, A yields 

 amoebae, B monads, and C vibrions. M. d'Auvray states that he is preparing a 

 work on this subject, and when the details are known his experiments can be 

 checked by other observers. One of his most remarkable statements that demand 

 verification, that some germs are able to withstand strong acids, prolonged boiling, 

 or attempts at calcination, by passing the air containing them through red hot 

 tubes. 



Coilins' Binocular Microscope. — This is a large, handsome instrument, 

 presenting some novel and ingenious peculiarities. It carries two object-glasses 

 on a dovetailed arm, sliding in a groove, so that a change of powers can be 

 instantly made. We should think this mode of construction would require even 

 greater attention to accuracy than the ordinary double nose-piece ; but, if accu- 

 rately centered, it affords certain advantages. The next important speciality is 

 the facility with which the polarizer (carried under the stage) can be brought 

 into play, and the analyser made to replace the prism of the binocular arrange- 

 ment, by drawing in or out the slide which carries both. In certain chemical and 

 medical investigations, these arrangements are very convenient, and several emi- 

 nent members of the medical profession have expressed great satisfaction with 

 Mr. Collins' labours. 



The stage is furnished with a magnetic bar, and if likewise supplied with the 

 ordinary object-holder and clip, its range of utility would be [increased, as the 

 magnetic plan, though good for slides, is not well adapted for heavier articles like 

 zoophyte troughs. We carefully examined the optical part of one of these instru- 

 ments and found it fully equal to all ordinary requirements. Mr. Collins has 

 taken an honourable place amongst those opticians who offer students a great deal 

 of convenience for a small sum of money. In first-rate, costly instruments all 

 kinds of wants are provided for ; but where price is an object, the purchaser 

 must consider what he stands most in need of, and what he can best dispense 

 with. Under such circumstances tastes and necessities will lead to much 

 difference of opinion, but it would be admitted on all sides, that Mr. Collins' 

 binocular is well entitled to consideration, and likely to meet the wishes of a large 

 class. 



New Source of Potash. — A coral-red subtransluccnt mineral, reported 

 to have been obtained from Cheshire, has been submitted to analysis by 

 Professor Church. He has identified it with the carnallite of M. H. Eose ; it 

 contained 25'7 per cent, of chloride of potassium. It is most probable that this 

 rich source of potash overlies the rock-salt beds of this country as well as those of 

 the foreign localities where carnallite has been found. It has been suggested that 

 it was formed in the last stages of the drying up of ancient seas. 



