640 REPORT— 1889. 



did not regard miners as a class strongly predisposed to any particular kind of ail- 

 ment in marked excess of others of the industrial classes. 



Ironstone and lead miners do not suffer in any special way ; hut the workers 

 in iron — particularly the puddler and striker — are apt to suffer from disease of the 

 heart and aorta owing to the strain thrown upon their blood-vessels. 



Although lead miners escape, lead smelters and all who are engaged in the 

 manufacture of lead — particularly white lead — run a very great risk of being con- 

 taminated sooner or later. Tyneside is the chief centre of the lead trade, and 

 unfortunately it supplies the opportunity for the study of plumbism in all its 

 phases. Dr. Oliver showed that whilst the more chronic effects of lead-poisoning 

 were found chiefly in the kidneys and nervous system, the acutely fatal form of 

 plumbism attacks young girls, from the ages of 18-23, who have only worked in 

 the white lead for a few weeks or months. In them a toxaemia is quickly deve- 

 loped : headache, blindness, colic, disordered menstruation, are the symptoms com- 

 plained of ; and unless those thus suffering are at once removed from the leadworks 

 and carefully treated — nay, even then — death may follow — epileptic convul- 

 sions and coma, as a rule, preceding the fatal event. In many of the internal 

 organs, post mortem, lead has been found, but in very small quantities — not more 

 than a grain or two in the brain^ for instance. As death under these circumstances 

 has been rapidly induced, no marked structural change is detected in the internal 

 organs. The pathology of chronic lead-poisoning is structural alteration of heart 

 and kidneys, and central and peripheral changes in the nervous system. 



Beyond suffering from bronchial affections, chemical labourers and millers have 

 no special disease that can be regarded as their own ; nor do cement-makers, 

 workers in copper, cattle-drivers, suffer from any special illness. Shop-girls and 

 milliners suffer largely from anaemia, and the former from the mechanical effects of 

 being too much on their feet. 



The question of the price of food, house accommodation for the working classes, 

 and overcrowding was next dealt with. Recent town improvements had necessi- 

 tated the demolition of many houses occupied by the labouring classes, and these 

 had not been rebuilt. As a consequence, a large body of the people had removed 

 to the outskirts of the town. 



The vice which seems to be on the increase amongst the working classes of the 

 district is betting. This was thought to be confined to some trades more than 

 others. 



6. Note on the Importation and Colonisation of Parasites and other Natural 

 Enemies of Insects injurious to Vegetation. By 0. V. Riley, Ph.D. 



The encouragement of the natural checks to the increase of insects injurious to 

 vegetation may be of a twofold nature. It frequently happens that an indigenous 

 species is found to have certain parasites in only a portion of the country which it 

 inhabits. In such cases, where it is practicable to transport the parasites, a great 

 deal of good may be accomplished. Oases in point are not uncommon. Some of 

 the Chalcid and Mymarid parasites of certain scale-insects (family Coccida) are 

 thus easily sent from one place to another (cf. my third, fourth, and fifth reports on 

 'The Insects of Missouri,' 1870-72). Again, in the case of the Plum-curculio 

 {Conotrachelus nenuphar), a widespread indigenous snout-beetle which seriously 

 affects the plum and a great deal of other stone fruit in the United States, this 

 beetle is known to have certain Braconid parasites, which undergo their transforma- 

 tion below ground, the larva forming a tough cocoon, in which it or the pupa is 

 easily transported by post or otherwise. ( Vide third report, ' Ina. Mo.' 1870.) 

 Other similar cases will occur to the experienced. 



But this intentional distribution of the parasites or natural enemies of an 

 injurious insect from one part to another of its native country is by no means to be 

 compared in importance with the introduction of such parasites or enemies from 

 one country to another, in which the injurious species has obtained a foothold, 

 without the corresponding natural enemies which serve to keep it in check in its 

 original home. 



