620 Microscopic Organisms in Blood of Man and Animals. [part hi, 



asserted that his parasite is not only identical with Dr. Salisbury's but also identical with 

 the Filaria sanguinis hominis* a figure of which under a somewhat like magnifying 

 power will be found in Plate XLII (Figs. 3 and 5). Dr. Douglas Cunningham several years 

 ago pointed out that such a view was untenable ; f moreover, the mature Filaria san- 

 guinis hominis is not oviparous but viviparous. 



D.— Changes undergone by the Embryos of Nematoid Haematozoa when ingested by 



the Mosquito. 



It would occupy too much space to attempt an epitome of all that has been 

 written regarding the Filaria sanguinis hominis and the somewhat numerous diseases 

 which have been ascribed to its influence, so that for the present the foregoing must 

 suffice. It remains to be considered how it is that the embryos get into the circula- 

 tion and what becomes of them afterwards. A most important step towards the solu- 

 tion of these queries has recently been made by Dr. Patrick Manson of Amoy.j He 

 has shown that, immediately after a mosquito has fed itself on the body of a filaria- 

 afFected individual, the insect's stomach will contain living examples of the hsRmato- 

 zoon ; and that the latter will attain considerable progress towards maturity therein , 

 in the course of a few days. It is believed that it then escapes from the mosquito 

 when the latter dies in the water to which it betakes itself, and filariae thus find their 

 way into the human body. Dr. Hanson's highly interesting paper gives a full account 

 of the various development stages, together with figures of the objects as they appear 

 from time to time. 



I have repeated many of Dr. Manson's experiments, and have been able to satisfy 

 myself, from personal observation, that his statements as to what occurs in China 

 may, in most particulars, be made applicable to India also. I had on many occasions, 

 examined the stomachs of mosquitoes and of other suctorial insects in a cursory fashion 

 during the last few years, but had never detected parasites resembling the Filaria 

 sanguinis. When, however, I learnt of Dr. Manson's success, I proceeded to make 

 examinations in a systematic manner, and found, to my surprise, that 14 per cent, of 

 the insects, caught at random and then examined, contained such embryos. § It became, 

 therefore, manifest that filarious blood must be a tolerably common occurrence. 



At first I was not successful in being able to detect any but disintegrative changes 

 in the ingested parasite owing to the circumstance that I had carefully restricted the 

 examination to the contents of the stomach only. This was done in order to diminish 

 the risk of confounding the various stages which the embryo-filarise might undergo 

 with some other parasites which might exist among the tissues of this, as of other 

 insects. The parasites were, in fact, found to be digested. Leuckart | mentions that 



* London Medical Record, No. I, vol. i, 1873 : The Lancet, July 13, 1878, p. 64. 



t The Lancet, June 14, 1873, p. 835. 



\ China Customs Beport, No. XIV, 1878. 



§ Proceedings of the Asiatic Society of Bengal, March 1878, p. 89, 



II Op. cit.. Band II, p. 706. 



